Immunology Flashcards
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors 3D folded structure.
Cells and antibodies can recognize
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
T cells only recognize this one when in certain length and presented by mhc.
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Polyclonal antiserum and B cells
Different epitome specificity.
B cells produce antibodies to different epitome but specific to 1 bacteria
Monoclonal antibodies and B cell
Important in pharmaceutical therapies
B. Cell and daughter cells produces antibodies that recognize same 1 epitome
Immunogens
Produce good immune response
Can bind AND induce an immune response.
Subsequent exposures result in increased responsiveness.
Proteins tend to be more immunogenicity than lipids carbohydrates and nucleic acids.
Why are proteins more immunogenicity
More specific to pathogen. Can tell difference.
Haptens
Don’t illicit immune response.
Need a carrier molecule
Small molecules that can bind to antibodies and receptors but cannot induce an immune response by themselves.
Can be immunogenicity when linked to carrier.
Tolerogens
Illicit little bit of immune response
Small but exposed over and over again for tolerance
Can bind and induce immune response.
Subsequent exposures or a different route of exposure results in decreased responsiveness
Explain how the new treatment for reversing a peanut allergy works, as well as drawbacks of this treatment
Using tolerogens.
Exposed to small doses of the peanut antigen over and over again can build a tolerance / decreased responsiveness.
Drawbacks are that if too much time elapses between doses or completely stop use can result in a worse reaction
Mitogens
Super immunogen
Strong nonspecific response.
T and B cell response
Polyclonal activators
Polyclonal activators
Mitogens
Induce nonspecific division and differentiation.
Response is not directed at specific antigen
T cell polyclonal activators
Produce nonspecific cytokines and nonspecific killing
B cell polyclonal activators
Nonspecific antibody production
Superantigens
Mitogens
Hold TCR:MHC together no matter what antigen is being presented and leads to unregulated cytokine production.
Cytokine storm
Produced by some pathogen.
Super activated >lots of clones > lots of cytokines> septic shock> immune cells to tissues> bp drops and edema
Adjuvants
Added to vaccines for boosted immune response
Patent protected so dont know exactly what it is
Factors that influence immunogenicity of proteins
Size Dose Route Composition Form Similarity to self protein Adjuvants Interaction with host MHC
Why does subcutaneous route increase immunogenicity. Why is intragastic the least?
Dendritic cells prevent it from gettin in. Dermatological response is the biggest part of the immune system
Gastric immune is the least amount. Don’t want to attack our healthy gut microbes, because inflammation is a huge problem there.
Why are large proteins more immunogenic
More surface area and epitopes
Why are less differences in similarity to self protein have decreased immunogenicity
Some bacteria make similar self antigens. The body’s respond to those antigens but then because they are so similar to self, they end up also attacking itself. >autoimmune
Antigen receptors adaptive and innate immune system
Innate immune system uses pattern recognition receptors (PRR)
B and T cells of the adaptive immune system have antigen specific receptors
Explain the pattern recognition receptors
Common component is recognized. Such as CPG repeats in pathogens since we do not have that.
Explain adaptive immune system antigen receptors
1 adaptive cell recognizes 1 epitope.
Innate antigen receptors
uses PRR to facilitate pathogen removal
Recognize PAMPs, pathogen associated molecular patterns
MAMPs microbe associated molecular patterns
DAMPs danger associated molecular patterns
PRR TLR
Toll like receptors
Membrane bound cell surface or in endosomes
Found predominantly on cells of immune system.
Have bunch of different ones specific to something/ component of pathogen
Flagella, parasite etc
Antigen receptors of adaptive immunity B cell receptors
B cell receptors recognize unprocessed antigen.
Recognize conformational and/or linear epitopes.
Can just bump into pathogen
Antigen receptors adaptive immunity T cell receptors
Recognize processed peptides presented by MHC molecules.
Peptides have to be linear and of a certain short length.
It is held for quite some time to recognize and then create antibodies for response. > why takes 8-10 days to have adaptive response and symptoms statutory to subside
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
Conformational epitope
Found in native structure Type of epitope recognized by Antibodies B cell receptors Innate receptors
Linear (continuous) epitope
Found in denatured structure
Only type of epitope presented by MHC and recognized by T cell receptors
Can also be recognized by antibodies / B cell receptors/ innate receptors
4 types of antigens
Immunogens
Haptens
Tolerogens
Mitogens
Primary (central) lymphoid organs
Site of lymphocyte production and maturation
Bone marrow, thymus, fetal liver
Secondary / peripheral lymphoid organs
Site of lymphocyte activation
Lymph nodes, spleen, mucosal associated lymphoid tissues (MALT)
Bone marrow
Responsible for formation of all postnatal blood cells.
B and NK cells continue to develop in bone marrow.
Red marrow
Highly vascularized spongy reticular framework filled with hematopoietic tissues
All lymphocytes begin development here
Thymus
Blooped gland above the heart
Encapsulated organ - 2 lobules cortex and medulla
Site of T cell maturation
Thymocytes
Progenitor T cells that enter thymus via small blood vessels
Embed in mesh work of stromatolites cells
Thymus cortex
Darker staining
More T cells
Thymus medulla
Lighter staining. Fewer T cells Dendritic cells Epithelial cells Macrophages Hassan’s corpuscles (but dont know what they do yet)
Thymus involution
Volume of active tissue decreases over time
Does not completely lose function
Lymph nodes
“Grand central station” of immune responses
Cells bring pathogens here to activate immune system
Antigens diffuse in via afferent lymphatic vessels
Dc migrate via afferent lymphatic vessels
Follow chemokine signals
What do lymph nodes swell
Commonly due to viral or bacterial infections
Can swell several times their normal size
May feel firm and look misshapen
Surrounding skin may be warm
Return to normal with resolution of infection
Spleen
Blood filtration system
Red pulp spleen
Phagocytosis of old or damaged RBC and antigens/microbes from blood
White pulp
Areas of lymphocytes around arterioles
Some separation of b and T cell areas
What happens if you don’t have a spleen
Life long risk of serious infection.
Most instances of serious infection are due to infections with encapsulated bacteria (just slip away)
Vaccination to minimize/prevent
Daily therapy commonly includes low doses of prophylactic antibiotics.
Mucosal immune system
Secondary lymphoid organ/tissue Encounters antigen/pathogens in great number and frequency compared to systemic GI tract Respiratory Urogenital Salivary
Peyer’s patches
Almost like lymph nodes without encapsulation
Mucosal layer of the gut
Lymphatic vessels system
Not closed loop - meets circulatory system
Where are lymphatic vessels found?
Everywhere except: Cartilage CNS Cornea Epidermis
Lymphatic vessels
Network of capillaries that transport cells and anything foreign from tissues to lymph nodes
How does lymph move
Result of muscle contraction and one way valves
Extravasation
Cell migration
Movement of blood cells through an unruptured vessel wall into surrounding tissue
Mediated by two groups of cell adhesion molecules (CAM)
Selectins and integrins.
Selectins
Rolling / weak adhesion. Post it note
Cell migration
Integrins
Tight adhesions - superglue
Cell migration
Chemotaxis
Receptor mediated movement of cells through tissues. Elicited by chemokines
Neutrophil migration to infection site
T/b cell migration to areas within secondary lymphoid tissues
Extravasation general process
Rolling adhesion,
Stable / tight adhesion
Rolling adhesion
A weak interaction between WBC and endothelial cell via selectins binding to ligand
Expression is constitutive, allowing all wbc to slow down in capillaries
Stable / tight adhesions
Strong interaction between wbc and endothelial cell via integrins binding to ligands
Expression is unregulated by inflammatory mediators, allowing wbc to adhere tightly and extravasated
Leukocyte adhesion deficiency
Genetic disorder characterized by deficiency of integrins
Marked by recurrent bacterial infections and severe neutrophilia (can get out of blood)
Lack of pus at infection sites.
Can’t exit vasculature to get to tissues
Chemokine directed migration
Cells follow concentration gradient of chemokine
Cellular movement depends on the chemokine and chemokine receptor
Homing of lymphocytes to specific areas of lymphoid tissue is mediated by chemokines.
Lymphocyte recirculating
Naive lymphocytes recirculate between blood and lymph until antigen encounter or death.
If antigen is encountered then activation, proliferation and differentiation
If antigen is not encountered then re enter blood/lymph after 1 day.
Enter lymph nodes via high endothelial venules, re enter blood via lymphatics and thoracic duct.
Enter and exit spleen through blood vessels
Functions of immune response
Recognition
Removal/restraint
Regulation
Memory
Antigens
Any molecule that can bind specifically to an antibody or antigen receptors on cells of immune system.
Epitomes
Smallest unit of an antigen that are recognized by antibodies and antigen receptors.
Can have 1 or more epitopes.
