02 T Cells

• polysaccharide capsules not recognized

Antigen presentation

• requires antigen presentation:

TCR

• CD3: E and Delta

• CD4: quarterback of immune response

CD4

MHC II

Co-Stimulation

TH1 and 2

• macrophages secretes IL-12

T Cell cytokines

TH1 vs 2

• Population of T cells; local cytokines favoring one or the other

• intracellular infections protected from antibodies because inside cell, Th2 not useful, Th1 cell mediated useful

Granulomas

Leprosy

IBS

TH1 and macrophages

• mutation in IL-12 or IFN-gamma receptors can lead to problem

IL12R deficiency

IFN-y

CD8

• antibody, APC, macrophages, CD4 are ineffective against intracellular virus
• CD8 react to MHC I and kill cell

MHC I

• heavy chain = alpha

CD8 function

Regulatory T

TH17

Memory T

• PPD test example of memory cell response

PPD

Superantigens

Thymus

• positive selection selects for strongest binding to MHC
• negative selection selects for weakest binding to self antigens

Aire