W1/Q1 Immunology intro Flashcards
Study of the molecules, cells, organs (immune system) responsible for responding to foreign material
Immunology
How does immunology/immune system work?
The immune system recognizes and eliminates foreign/”non-self” material
Activation - TCR bind and recognize cognate ligand antigen from MCH 2.
Creates cytokines -> Role - Activation of B and Tc cells
TcR-CD4+ T helper cells : Activation/Role
Activation - TCR bind and recognize cognate ligand antigen from MCH 1.
Role - kill infected/damaged cells
TcR-CD8+ T cytotoxic cells : Activation/Role
- non-specific- responds to groups, not individual pathogens
- fast - full capacity ready, many cells present, deployed rapidly
- no memory - multiple exposures create no memory, response is not augmented
Innate immune system characteristics
- specific - responds to a pathogen / foreign element
- slower - few cells have potential to respond, need activation and expansion
- memory - secondary exposures -> robust and fast response
Adaptive immune system characteristics
activation - B cells proliferate -> plasma cells secrete antibodies which combines with antigen; allows for immune system to Identify and neutralize pathogens aka antibodies
BcR
1st line of defense
Polymophonuclear cells (PMNs)
Segs (segmented)
Innate immunity
Circulating granulocyte
50-75% of WBCs
- Primary phagocyte and initiator of inflammation after a cut/scrape
- Main component of pus - yellow/white
- Granules w/toxic reactive oxygen species (ROS) to kill pathogens
Neutrophils
Foot soldiers - kill pathogens
Tissue specific
Expansions of outer membrane -> “decoration”
Innate immunity
Bridge between innate and adaptive immunity
Myeloid line
CD11C
- Phagocytosis of antigens and presentation to helper T lymphocyte
- Most potent phagocytic cell in tissue
Dendritic cells (Dcs) Foot soldiers/informants - Present and kill pathogens
Kill and present pathogens
Clean up
Innate immunity
Non-granulocytic myeloid cell
4-10% of WBCs
CD11b, CD14
- Phagocytes eat pathogens
- Present pathogen bits (antigens) to T cells
- Clean up debris from immune “fights”
Monocytes/Macrophages (MACs)
Foot soldiers / informants
Direct or stop B cells and CD8 Tc cells
TCR***
T lymphocytes (CD4 T helper)
Kill infected cells
Adaptive immunity
T lymphocytes (CD8 T cytotoxic)
Produce antibodies that neutralize/kill pathogens long distance
adaptive immunity
Archers/drone controllers
B lymphocytes
Circulating granulocyte
Myeloid line
0-2% WBCs
- Release histamines and other inflammatory mediators in allergic disease
- Regulate some T helper cell responses and stimulate B cells to produce IgE
* Mast cells are similar but in tissues
Basophil/Mast Cells
Myeloid line
1-3% WBCs
- Primary phagocyte against multicellular microbes (parasites)
-Neutralize basophil and mast cell products
- Regulation of mast cell function
Eosinophils
lymphoid line
10-15% of WBCs
CD56
- Kill tumor/infected target cells (does not need earlier exposure to them)
- Can be directly activated by no inhibitory signal or ADCC
Natural Killer Lymphocytes/Cells
MHC class 1 protein is expressed on healthy self cells and creates an inhibitory signal
- diseased/cancerous cells tend to lose MHC class 1 proteins -> killing of cells
- activating receptors engage with target cells and will result in killing unless inhibitory receptors are engaged
NK activation by Lack of inhibition
IgG binds to target cell through Fc portion and CD16 receptor -> IgG coated cells are bound and destroyed
- NK cells can recognize and lyse antibody - coated cells
NK activation by ADCC
(Antibody dependent cell cytotoxicity)
Perforins and granzymes are injected into cells (after activation)
- Cytokines produced (tumor necrosis factor)
NK Killing
Proteins that form channels (pores) in the target cell membrane
Perforins
Packets of enzymes that may enter through the channels and mediate cell lysis
Granzymes
