Helper T cells- Response to antigen Flashcards
Lymphocytes populations: Four major populations w/ antigen binding receptors
Helper T cells= regulate immune response
Cytotoxic T cells= destroy cells expressing endogenous antigens
Regulatory T cells= control everything
B cells= produce antibodies (adaptive immune response)
Main role of Th cells?
important cell regulator of the immune response
What would happen if helper T cells were not activated?
no immune response, no activation of B cells or cytotoxic T cells
TCR
made of 2 proteins variable region where antigen attaches α/β protein γ/δ protein -T cells -30,000 TCR receptors
MHC I
Big protein, α protein, microglobin
MHC II
α/β protein
BCR
similar to antibody, same chemical structure!
Big
-attached to cell membrane
-5 different types of receptors
T cell antigen receptor
- humans & mice
- cows/sheep/pigs
- α/β protein
- γ/δ protein
CD3 complex
- 5 protein chains (γ/δ/ε/η/ζ)
- protein dimers
- Complementary determining region (CDR)- recognize specific antigens
- Hypervariable sequence of amino acids
Antigen-presenting cell (normal)
*What kind of response?
- Dendritic cell
- MHC II antigen
- CD4
- interacting w/ T cell (Th)
- humoral immune response
Antigen-presenting cell (infected w. bact.)
*What kind of response?
- Cytotoxic T cell
- MHC I antigen
- CD8
- cellular immune response
TCRα
to recognize antigen & MHC
TCRγ
to recognize antigen
CD3
signal transducer
CD4
MHC II receptor
CD8
MHC I receptor
1st co-stimulatory signals
-APC: IL-1,6,8,12, TNFα, CCL3 (antigen presenting cells produce all these cytokines) proinflammatory cytokines
2nd co-stimulatory signals
-APC CD28-CD80
-B cells CD28-CD86
B cells can act as APC
ACTIVATION-8 fold
3rd co-stimulatory signals
CD152-CD80/86
INACTIVATION- T cell suppression
T cells IL-2
upregulate cell survival genes, increase energy metabolism, promotes T cell division
2 different types of dendritic cells:
- Myeloid precursor: Th1=cellular
- Lymphoid precursor: Th2=antibody/humoral
Th17 cell
promote adaptive immune response
IL-17
increase inflammation
Helper T cell
antibody/humoral mediated cell response
The variable domatin of the TCR is explicit for binding a specific antigen. T/F
TRUE
TCR, BCR, MHC I & MHC II are not members of the immunoglobulin superfamily. T/F
FALSE: they ARE members
If a processed and presented antigen bind in a correct manner on a T cell, T cell is activated and initiates the immune response by:
cytokine production, mitosis, cell differentiation
CD3 is found in all T cells and it has a main role in the signal transduction into the T cell. T/F
TRUE
