learning outcomes? Flashcards
list the major cells involved in the innate and adaptive immune system
Innate:
- phagocytes (macrophages-redness,swelling, neutrophils-WBC, eosinophils-digestive enzymes,basinophils, mast cells- allergy, anaphalactic)
- Natural killers- perforin
Adaptive:
-T cells ( T-helper- CD4, T-killer- CD8, T-memory-partially differentiated)
main roles of the innate system?
- phagocytosis
- activation of T-cells which then lead to activation of B-cells
- cell Lysis through MAC-MEMBRANE ATTACK COMPLEX
- inflammation
- opsonisation
describe the function of NK
Has a role mid way between phagocytosis and T-killer.
- 2 receptors. one which leads to cell death, one which doesn’t.
- releases perforin onto cell surface and leads to apoptosis
describe the role of phagocytosis and intracellular death?
Phagocytosis
1- phagocyte moves towards microbe due to difference in concentration-chemiosmosis
2- phagocyte engulfs the microbe to form a phagosome
3-lysosome binds to phagosome to form phagolysosome
4-releases digestive enzyme which break down the phagolysosome
5- materials are discharged
Intracellular death:
-prevents cells which recognise self from attacking self material-autoimmune disease.
describe the primary and secondary lymphoid organs?
primary:
- bone marrow: haematopoiesis
- thymus: helps in T-cell differentiation
secondary: purifies lymph before it enters blood, produces B-cells and maintains T-cells, removes antigens
- spleen
- tonsils
- lymph nodes
- peyer’s patches
properties of the adaptive immune response?
- specific
- produces memory cells
- takes longer to respond
- cells involved are lymphocytes
- proteins involved are antibodies
- cellular barrier are lymphocytes in the epithelium
describe the role of B-lymphocytes in immune response
1- production of antibodies by the T-cell dependent or the T-cell independent pathway
2- produce memory cell which help secondary response
structure of an antibody?
Function of the antibody?
two chains. one heavy, one light. Linked by disulphide bridges.
constant region and variable region.
constant region is the same for all immunoglobulins in the same class.
variable region is different in each B-cell.
binds to the antigen.
IgM- leads to ospinisation. activates complementary system.
IgG-leads to ospinisation, can pass through plasma
IgA- involved in neutralisation
IgE- involved in allergy response and anaphylactic response
IgD- function unknown
describe the role of T1 and T2 helper cells in immune system.
Th0 bind to antigen presenting cell.
They differentiate into Th1-lead to the production of T-memory cells- and Th2- lead to the production of B-cells.
B-cells differentiate into Plasma cells which produce antibodies or B-memory cells.
briefly describe the complement system and its function?
complement system:
- cell lysis via membrane attack complexes
- ospinisation
- inflammation
- B- cell activation
made up of 20 different serum proteins. can be activated by different pathways.
Classic:
C1 protein binds to antigen-antibody complex. leads to cleavage of C2 and C4. C2b and C4b react to form C3 converts. C3a and C3b formed. C3a leads to inflammation. C3b leads to ospinisation by binding to microbes and increasing the chances of phagocytosis.
C3b can also cleave into C3d which binds to a B-cell. epitopes bind to IgM at the same time which stimulates B-cell activation.
cytokines as messengers in the immune system?
chemicals which allows cells to communicate with one another. binds to receptor on target cell leading to biological response.
AUTOcrine
PARAcrine
ENDOcrine
