Adaptive Immunity- Diebel Flashcards
What is an epitope?
Small part of an antigenic molecule, 10-20 amino acids
Region on antigen that can be recognizes by an antibody of by T-cell receptors (aka antigenic determinants)
How long does it take for the adaptive immune response activation?
7-10 days
Describe the different roles of T and B cells in the adaptive immune response?
B-cells protect the extracellular spaces - fluids blood secretions by releasing antibodies
T-cells- in charge of cell-mediated immunity (surveys the surface of body’s cells)
What is the difference between class I and class II antigens?
Class 1 = antigens synthesized within the cells (recognized by CD8+ Killer T-Cells)
Class 2 = antigens are products of phagocytosis (recognized by CD4+ Helper T-cells)`
What is CD3?
T- Cell Receptor!! (TCR)
What is the big difference between gamma-delta and alpha-beta T cells?
alpha beta must bind antigen+ MCH1 or MHC2
gamma-delta T-cells can function with out binding MHC and protect the mucosal surfaces of the body
The alpha-beta T-cell receptor will bind what on APCs?
Antigen
What does the CD4 or CD8 molecule on the T-cell bind to?
CD4= MHC 2 CD8 = MHC 1
What molecules act as a co-stimulatory signal for T-cell activation?
CD28 on the T-cell binds to CD80/86 on the APC
What molecular interactions act to strengthen the adhesion between a T-cell and APC during the process of T-cell activation?
ICAM-1 on APC binds LFA-1 on TC
LFA-3 on APC binds CD2 on TC
Role of Th1?
- makes lymphokine that attracts MACs
- INTENSE inflammation
Role of Th2?
stimulate MACs to become “alternatively activated”
helps to wall off pathogens
promote healing
usually takes place after Th1 response
important in parasite immunity
Role of Th17?
Focused inflammation
More powerful than Th1
Implicated in serious forms of autoimmunity
Role of Follicular Helper T-cells? Tfh
stimulated by antigen
migrate from t-cell areas of lymph nodes into the B-cell follicles
help get B-cells activated and make the antibody subclass
Role of T regs?
Make cytokines that suppress the activation and function of Th1, Th17, Th2
Role of cytotoxic or killer T-cells?
Destroy any body cell they identify as bearing a forgien or abnormal antigen on its surface
What cytokines are general activators/ proproliferative of T-cells?
IL-2
IL-15
What cytokines drive differentiation towards Th1?
IL-12 and IFN-gamma
What cytokines drive differentiation towards Th2?
IL-4
Where would you find MHC Class I molecules?
ALL CELLS! except for red blood cells
Describe function of Killer T Cells
Killer T cell recognizes abnormal antigen on MHC I molecule
expands and daughter cells circulate
once found the correct antigen, t-cell delivers lethal hit
Signals to cells to commit suicide through apoptosis
T-cells express FAS ligand, which binds to FAS on target cells and activates caspases
Also kills by releases cytotoxic agents (TNF, perforin, granzymes)
What different molecules do T and B cells secrete?
B lymphocytes secrete antibodies
T lymphocytes secrete short-range cell mediators = lymphokines (subset of cytokines)
Function of IgG
Two adajecent IgG bind antigen
cooperate to activate complement
What is the only antibody that can cross the placenta and protect a newborn?
IgG
