1.1 Basic concepts in immunology Flashcards
Immune system function:
Protect the host from infection
- detection and destruction of infectious organisms
- remember what they look like, in case they come back (memory)
Immune system structure types:
- white blood cells
- lymphoid tissues
2 types of host immune response:
- innate immunity
- adaptive immunity
Innate immunity:
- tries to keep foreign organisms out
- can recognize that infection is present and respond quickly
adaptive immunity:
- much more efficient, slower to react
- helps innate immunity work better
Innate immunity detection strategy:
Uses pathogen-associated molecular patterns (PAMPs) to recognize molecules that are intrinsically foreign
- Neutrophils + tissue macrophage target bacteria
- eosinophils + tissue mast cells target parasites
Have broadly reactive receptors that arent very specific?
innate immunity
neutrophils + tissue macrophage target?
bacteria
eosinphils + tissue mast cells target?
parasites
PAMPs: LPS =
LPS = gram -VE bacteria
PAMPs: Peptidoglycan =
Peptidoglycan = gram -VE bacteria
issue with innate immunity?
innate immunity and PAMPs:
- viruses have a simple structure, less obvious PAMPs
- some bacteria produce capsule to hide PAMPs
Addaptive immunity is expressed by ?
Lymphocytes
Lymphocytes:
- recognizes foreign antigen
- Highly specific detection system
antigenic epitope:
small region of foreign antigen
Antigen:
structural protein of pathogen
Primary role of Lymphocytes?
- Have T cells and B cells
- primary role = dealing with viruses
**assist innate immunity bacterial and parasite infections
B cell receptor:
bind WHOLE antigen on surface of pathagen in ECF
B cell response to infection:
T cell receptor:
recognizes DIGESTED antigen (peptides) displaced on surface
role of immunolgical synapse:
gets info about infection from 1 cell to another cell
Where does the lymphocyte develop?
Bone marrow
- develops unique antigen receptor
When the receptor binds to an antigen it recognizes?
the lymphocyte is activated
- only lymphocyte activated is the one that recognizes that specific antigen
- this means only a few will react out of thousands
**think of blind men and elephant
Which clonal type recognizes infection?
2
Jobs once activated: B cells
produce antibodies —> stick to pathogen
Jobs once activated: CD4 T helper cells
produce cytokines —> these activate other cells
Jobs once activated: CD8 killer T cells
seek out and destroy virus-infected cells
Antibody:
antigen binding protein
- targets the external surface of the pathogen like a molecular heat seeking missle
What happens once an antibody is bound to a pathogen?
- inactivates/neutralizes it
- attracts phagocytic cells to eat it
- triggers innate killing response (complement cascade)
Cytokines are used to:
- activate macrophage
- assist B cells in making antibodies
Lymphocyte clones =
lymphocyte memory
- in case the pathogen returns
- allows the immune system to respond much more quickly than previously
- Host develops immunity / immunological memory
