Immunology Flashcards
What is the primary function of the immune system?
To protect against pathogens.
What is a pathogen?
Any organism which can harm the body.
Give some examples of common pathogens.
Bacteria / viruses / parasites / fungi / protzoa.
What are the 2 division of the immune system?
Innate immunity
Adaptive immunity
What is the innate immune system?
The first to come into play- it is non-specific and will produce a response time and time again without capacity for immunological memory.
What is the adaptive immune system?
Takes a few days to come into play- it is highly specific and will have capacity for immunological memory.
Is innate or adaptive immunity the first to come into play?
Innate.
What type of immunity is highly specific?
Adaptive.
What type of immunity has the capacity for immunological memory?
Adaptive.
Does innate immunity have the capacity for immunological memory.
No.
What must a pathogen do before it can infect the body?
Attach to and penetrate the epithelial barriers of the body.
How can the skin defend against pathogens?
Cilia- hair-like structures found in nasal passages to sweep pathogens away
Mucosal epithelial cells produce mucus to coat surfaces
Tears/sweat have a flushing action.
What are cilia?
Hair-like structures found in nasal passages to sweep pathogens away.
How does sweat defend against pathogens?
High in NaCl / lysozyme.
How does the stomach protect against pathogens?
Acidic environment and secretion of digestive enzymes.
What do tears and sweat contain that can protect against pathogens?
Lysosomes.
What is utilised in innate immunity?
Composition of blood.
What components of blood are utilised in innate immunity?
Plasma- complement proteins / cytokines
WBC
What are leukocytes?
White blood cells.
How are WBC derived?
Leukopoiesis.
What 4 types of WBC are seen in innate immunity?
Neutrophils
Macrophages (monocytes)
Eosinophils
Basophils
What are the most abundant WBC in blood?
Neutrophils.
What do neutrophils do?
Most abundant, effective phagocytes, fast response to stimuli.
Do neutrophils have a fast response?
Yes- but short half-life.
What happens in phagocytosis?
Phagocyte moves to pathogen, attaches it, endocytosis and destruction through lysosome occurs.
What is phagocytosis?
Cell eating.
What do macrophages do?
Migrate into cells and form phagocytes.
Process antigens and present them to immune system.
How does macrophage phagocytosis compare to neutrophil phagocytosis?
Macrophages engulf way more.
Do neutrophils or macrophages carry out most of phagocytosis?
Macrophages.
Do neutrophils or macrophages appear first in tissues?
Neutrophils.
How do macrophages act regarding antigens?
Process antigens and present them to the immune system.
Do macrophages have a longer life span than neutrophils?
Yes.
What do eosinophils do?
Help combat parasitic infection.
What type of cell primarily helps combat parasitic infection?
Eosinophils.
What conditions are eosinophils often involved in?
Allergy and asthma.
What do eosinophil granules contain?
Many enzymes.
What can mast cell activation lead to?
Anaphylactic shock through hypersensitivity and autoimmunity reactions.
What stimulates mast cell activation in the hypersensitivity I response?
Immunoglobulin E binding to FceR1 receptors.
What are basophils?
Least common WBC, contain large cytoplasmic granules with inflammatory mediators, no proven function, found in parasitic infection.
What are the least common WBC?
Basophils.
What type of infection are basophils often seen in?
Parasitic.
Do basophils have a proven function?
No.
What do basophils contain?
Large cytoplasmic granules with inflammatory mediators?
What type fo WBC contain large cytoplasmic granules with inflammatory mediators?
Basophils.
What are natural killer cells?
Important part of innate immunity as they kill viruses, bacteria, infected cells and cancer cells.
Can natural killer cells kill cancer cells?
Yes.
What is the complement system?
The complement system is a family of 20 different proteins in the blood plasma which are involved in killing microbes and enhancing the immune response.
How is the complement system activated?
Like a cascade- they interact sequentially with each other.
What does the complement system ultimately lead to?
Microbe lysis.
Where does the complement system exist?
Blood plasma.
What are cytokines?
Cytokines are small proteins secreted by immune cells in response to a stimulus.
What do cytokines do?
Communicate with other cells and affect their behaviour. They are ultimately signalling molecules which have a role in innate and adaptive immunity?
What are signalling molecules called?
Cytokines.
What are cytokines secreted by and why?
Secreted by immune cells in response to a infector stimulus.
In what type of immunity do cytokines play a role?
Primarily innate but are effective in both.
What is the inflammatory response?
General term give to the protective response given by all WBC in response to damage/infection which involves healing and repair.
What does the inflammatory response work to do?
Destroy the pathogen/microbe and work to heal and repair the tissue.
What are the symptoms of the inflammatory response?
Cardinal signs of dolor (pain), calor (heat), tumour (swelling), rubor (redness), and loss of function.
What is the inflammatory response often affected by?
Chemical mediators such as C3a / C5a.
In what responses is the inflammatory response often initiated?
Hypersensitivity and autoimmunity responses.
What are the functions of the lymphatic system?
Drainage of fluid, immunity, absorption/transport of fats and fatty acids.
What is the lymphatic system composed of?
Lymphatic vessel Lymphatic organs (primary / secondary)
What are primary lymphoid organs?
Places where blood cells are produced and receive their early training.
Give two examples of primary lymphoid organs.
Bone marrow
Thymus
What are the bone marrow and thymus examples of?
Primary lymphoid organs.
What are secondary lymphoid organs?
Sites of lymphocyte activation by antigens.
What lymphoid organs are sites if lymphocyte activation by antigens?
Secondary lymphoid organs.
Give 2 examples of secondary lymphoid organs.
Lymph nodes
Spleen
What are lymph nodes?
Encapsulated, vascularised organs which are located around the body- they have access to antigens encountered in most tissues and function to produce an adaptive immune response.
What type of immune response to lymph nodes function to produce?
Adaptive.
What is the spleen?
Organ in UL abdominal quadrant which functions to filter. blood.
What is the function of the spleen?
Filtering blood.
What does red pulp contain in the spleen?
Different types of blood cell.
What does white pulp contain in the spleen?
Lymphocytes.
What are the lymph nodes and spleen an example of?
Secondary lymphoid organs.
What is MALT (Mucosal Associated Lymphoid Tissue)?
Own system of lymph nodes which some areas of epithelium have.
What is an example of MALT?
Peyer’s Patches.
What are Peyer’s Patches?
Patches of smooth cells embedded in the villi-covered small intestine.
What do smooth cells embedded in the villi-covered small intestine form?
Peyer’s patches.
What are the tonsils an example of?
Lymphoid tissue.
What are the 3 stages of immune defence?
Recognition of danger
Production of specific weapons
Transport of weapons to the site of attack
What are the two types of T-cell?
CD8 cytotoxic T cells
CD4 helper T cells
What do cytotoxic T-cells do?
Release perforin when exposed to infected/dysfunctional somatic cells. Forms pores on the target cell and can initiate apoptosis.
What do cytotoxic T-cells release?
Perforin.
What process can cytotoxic T-cells induce?
Apoptosis.
What do helper T-cells do?
Cannot kill the infected cell or pathogen- they activate and direct other immune cells and are essential in the activation of Tc cells.
Can helper T-cells destroy the infected cell or pathogen?
No.
What are helper T-cells essential in the activation of?
Essential in the activation of cytotoxic T-cells.
What receptors are on cytotoxic T-cells?
CD8+ receptors, recognise antigen when bound to MHC 1.
What must CD8 receptors be bound to in order to recognise the antigen?
MHC I.
Where is MHC I found?
Virtually all nucleated cells.
What does MHC I present?
Presents virally induced peptides to trigger cytotoxic response.
What type of T-cell receptors recognise antigens when bound to MHC I?
CD8+ cytotoxic.
What type of MHC is found in virtually all nucleated cells?
MHC I.
What type of MHC presents virally induced peptides to trigger a cytotoxic response?
MHC I.
What receptors are on helper T-cells?
CD4+ receptors, recognise antigen when bound to MHC II.
What must CD4 receptors be bound to in order to recognise the antigen?
MHC II.
Where are MHC II found?
Professional Antigen Presenting Cells.
What does MHC II do?
Presents exogenously produced Ag to T-cells.
What does MHC II activate?
B-cells and macrophages.
What type of T-cell receptors recognise antigens when bound to MHC I?
CD4+ helper.
What type of MHC is found in Professional Antigen Presenting Cells?
MHC II.
What type of MHC presents exogenously produced Ag to T-cells?
MHC II.
What type of MHC allows activation of B-cells and macrophages?
MHC II.
What must T-cells learn not to recognise?
Self-antigens and Ag with own MHC.
What does the learning of T-cells not to recognise own antigens/MHC give rise to?
Positive selection
Negative selection
No selection
How can immunological memory arise?
Immunological memory can arise from fully or partially differentiated T-cells which allows the potential for further differentiation on secondary exposure with antigen.
What requires fully/partially differentiated T-cells?
Immunological memory.
What is the humeral immune response mediated by?
B-cells.
What is cell-mediated immune response mediated by?
T-cells.
What are B-cells involved in?
Humeral immunity.
Where are B-cells produced?
Bone marrow.
What do B-cells develop into?
Plasma cells.
What do B-cells express?
Surface immunoglobulin.
What type of cell expresses surface immunoglobulin?
B-cells.
What does surface immunoglobulin act as on B-cells?
Antigen receptor.
When are B-cells developed into plasma cells?
On activation for antibody production.
What does conversion of B-cells into plasma cells allow?
Antibody production.
Why is it more important to tolerise T-cells than B-cells?
Because B-cells require T-cells for antibody production.
What do B-cells require for antibody production?
T-cells.
What are antibodies?
Largest Y-shaped protein used to neutralise pathogens.
What are antibodies called?
Immunoglubulin (5 types).
What shape are antibodies?
Y-shaped.
How many types of antibodies are there?
5.
What is active immunity compared to passive immunity?
Active immunity- from hosts own immune system
Passive immunity- transfer from other individual
Does active or passive immunity develop faster?
Passive.
Are memory cells produced in active / passive immunity?
Produced in active immunity but not passive.
Is protection permanent in active / passive immunity?
Permanent in active immunity.
What are natural and artificial sources of active immunity?
Natural - infection
Artificial - vaccination
What is a source of passive immunity?
Mother to child.
