Overview of the immune system Pt 1 Flashcards
What will a properly functioning immune system mount a response against
Dangerous non self
What does immune system do
Fight pathogens
Name and describe pathogen categories
Viruses
Parasites
Bacterium
Fungus
What are immune responses…
Quickly tailored to type of microorganism involved
Each v diff
Depends on pathogen we are exposed to
Diverse and tailored
Do different pathogens require the same immune response
NOOO
Require diff immune responses
What is one major difference - for pathogens
Intracellular = virus
Extracellular = bacteria, replicate outside cell
Immune response v diff
Pathogens are processed differently and generate diff types of responses
Describe immune response
Complex and involved many molecules, cells and tissues over time and in diff locations
Can sometimes result in life long immunity
Describe the 2 interconnected systems that the immune system uses in response to pathogens
In response to pathogen =
Innate immunity = first line of defence, fast non specific
Adaptive = highly diverse and specific
Need both
Name major players In immune response
Key organs and tissues
Cells
Molecules
Describe organs and tissues of immune system
Collection of organs, tissues, cells and molecules that cooridnately work to protect from infection
Describe key components of organs and tissues
Bone marrow
Thymus
Lymphatics - lymphatic system
Lymph nodes
What do immune cells do
Travel in body and occupy diff tissues over time
Through blood or lymphatic system
What are primary lymphoid organs
Where immune cells developed
Where immune cells generated
CENTRAL
Bone marrow and thymus
What are secondary lymphoid organs
Where immune response initiated
Where immune cells activated
PERIPHERAL
Connected to each other via blood and lymphatic circulatory systems
LYMPH NODES, SPLEEN, MALT (mucosal associated lymphoid tissues), OTHER DIFFUSE AND LOOSELY ORGANIZED AREAS
What is important about immune cells
Diff immune cells associated with 2 diff categories = diff involved in diff ones
Innnate = neutrophils, mast cells, monocytes
Adaptive = b and T cells
Both = nk cells, dendritic, macrophages
Describe names of immune cells
Leukocytes or wbcs
Where do immune cells originate
Bone marrow
Where do all mature blood cells come from
Single cell type. = HSC
Hematopoietic stem cell
What is hematopoiesis
Process by which HSCs differentiation into mature blood cells = occurs in bone marrow
Describe hematopoietic stem cell
Pluripotent / multi potent
Define pluripotent
Stem cells can generate almost every specialized cell type in an organism
Define multi potent
Stem cells generate various cell types on family - one type - of related cells
Name 2 main lineages
Lymphoid = B cells, T cells, nk cells (type of ilc), ilcs (innate lymphoid cells), give rise to adaptive immune cells
Myeloid = other leukocytes
What can dendritic cells be generated by
Both lineages
Go to reside to tissues and organs or circulate in blood or lymphatic system
What is from myeloid lineage
Rbcs = erythrocytes
Granulocutes
Megakaryocytes
Monocytes
Describe erythrocytes - myeloid lineage
Carry oxygen to cells and tissues
Can generate anti microbial compounds
Not key immune cells tho
Describe granulocytes - myeloid lineage
Neutrophils = direct harm to pathogens
Eosinophils = antiviral activity, anti parasitic activity
Basophils/mast cells = inflammation/allergies, creates histamine
Describe megakaryocytes - myeloid lineage
Give rise to platelets - blood clotting
Describe monocytes - myeloid lineage
Migrate into tissues and differentiate into macrophages —> function to repair/remodel, destroy pathogens and present antigens (triggers immune responses)
Which cells are specialized for phagocytosis - myeloid lineage
Macrophages
Immature dendritic cells
Neutrophils
Phagocytosis = cellular uptake by engulfment
Describe what dendritic cells do exactly
Immature dendritic cells capture antigens, once they phagocytose = then mature and migrate out of that location to another and present antigens to T cells
DENDRITIC CELLS = MOST POTENT APCs for activating naive T cells = bridge gap, most important role of dendritic cells
Describe lymphoid lineage
3 main types of cells = b, t and natural killer cells (subtype of innnate lymphoid cell) and ilcs
Describe lymphocytes
Appear similar but different sets carry diff clusters of differentiation = CD molecules on their surface
Describe lymphocytes and specificity
T and B cells responsible to adaptive immunity
Generate highly specific responses
Specificity determined by expression. Of receptors on cell surface
Bcr
For B cells
Can be bound to membrane or secreted as antibodies
Tcr
Membrane bound
Always anchored
What do dendritic cells bridge
Key bridge in immune response
Connected innate to adaptive
Involved in detecting infection
Activate adaptive imminuty
T OR F innate and adaptive immunity work entirely separate
NAWHWHWHWHWH
Work COOPERatively
What does activation of innate immune response produce
Signal molecules = communication
Stimulate and direct adaptive immune responses
What can signal molecules do
Function to communicate - between cells or inside cells - or mediate interaction between cells
Molecules trigger changes in target cells = activation, signalling, migration, transcription, cellular differentiation…
Molecules = communicate but also can change cells, like matures dendritic cells
Name 4 key types of molecules
Secreted proteins
Receptors on cell surface
Intracellular signalling molecules and transcription factors
Antigens
Describe secreted proteins
Cells communicate with each other through cytokines and chemokines
What are cytokines
Messenger proteins secreted by certain cells
What are chemokines
Subset of cytokines that recruit specific cells to a site
Describe receptors on cell surface
Immune cells covered in receptors
Cytokines and chemokines bind target cells via specific receptors
Cells can interact with each other through receptors
Describe intracellular signalling molecules and transcription factors
Many stimuli can result in intracellular signalling, involving signalling proteins and transcription factors —> something happens inside cell
Describe antigens
Molecules that immune responses are generated against - want to clear these
Describe ex =cells interact with each other via receptors, resulting in change = cell migration
Monocytes binds adhesion molecules on vascular endothelium near site of infection and receives chemokines signal
Interaction= it’s receptor of monocyte wth receptor of endothelial, chemokine binds —> these interactions lead to change= migration of cell into tissue
Monocytes mirgates into surrounding tissue
Monocytes differentiates into inflammatory monocytes at site of infection
Endothelial cell also has to loosen up = for cell to pass = also changes, happening in cell, also differentiated bc intracellular signalling took place, cell migrates to higher concentration of hcmeokines - chemokines will influence where cell goes
What is an antigen
Key molecule targeted by immune system
Immune response generated against key specific components
Specific molecule that can trigger immune response
What can an antigen be
Protein - most
Nucleic acid
Polysaccharide
Lipid
Organic chemicals
Drugs
What is epitope
Specific portion of Antigen recognized by a receptor on immune cells = epitope
B and T cell specific to each epitope
What is apart of innate immunity
Pathogen entry
Pathogen recognition by innate immune cells
Inflammation
Homing to LN
What is apart of adaptive immunity
T AND B CELL Activation
Adaptive immune response
Recognition and memory - hopefully
What links innate to adaptive
Dendritic cell links, goes to lymph node
What can macrophages also do
Present antigens to T cells
