T Cells Flashcards
IL-2
Stimulates T cells/NK cells
IFN-gamma
Stimulates macrophages
IL-4
Stimulates differentiation into Th2 and STIMULATES B CELLS - promotes class switch to IgE and G
IL-5
Stimulates B cells and class switch to IgA
IL-12
Induces differentiation of Ts into Th1 and activates NK cells
IL-10
Inhibits T cells and macs
Th1 Cells (secretions/actions, activated by, inhibited by)
Activated by IFN-gamma and IL-12 (from virally infected cells), so secretes IFN-gamma and IL-2 to activate macs and cytotoxic T cells
Inhibited by IL-4 and IL-10 (from Th2)
Th2 Cells (activated by, secretions/actions, inhibited by)
Activated by IL-4, so secretes IL-4 and 5 (for B cell activation), IL-10 (inhibit Th1 and macs) and IL-13. Recruits eosinophils for parasite defense and promotes IgE production/B cells
Inhibited by IFN-gamma from Th1
Naive T Cell Activation
DC expresses MHC which binds to TCR/CD, as well as costimulatory signal B7 (DC) to CD28 (naive T cell) inducing differentiation. MHC I - CD8 for cytotoxic T cells, MHC II - CD4 for T helper cells
B Cell Activation/Class Switch
Th cell (CD4, really Th2) has TCR which binds Ag in B cell MHC II. With costim signal (CD40L on Th and CD40 on B), Th secretes cytokines which determine Ig class switch/activation
3 Ways Cytotoxic T Cells kill Cells
Release granules of preformed prots: perforin forms pores, granzyme B is serine protease that activates apoptosis
Also express FASL which interacts with FAS (R) on host cell inducing apoptosis
Regulatory T Cells (2 notable CDs and cytokines)
CD25 and FOXP3
Produce anti-inflammatory cytokines IL-10 and TGF-Beta
NK Cells (advantage, enhanced by, when, mechs)
Don’t require Th signals like T cytos so quicker and more of innate response
Enhanced by IL-2, IL-12, IFN alpha and beta (those 2 also stimulate neighboring cells to destory viral protein synthesis so super important for viral infections
Induced to kill when exposed to nonspecific activation signal on target or absence of Class I MHC on target
Release perforin and granzymes also but also antibody-dependent cell-mediated cytotoxicity
Also secrete IFN-gamma to increase macs
Antibody-Dependent Cell-Mediated Cytotoxicity
CD16 binds Fc region of bound Ig, causing death of Ig-covered cells. CD16 found on NKs, macs, monocytes, and nphils
HLA B27
Risk for psoriatic arthritis, ankylosing spondylitis, arthritis of IBD, Reactive arthritis
PAIR - seronegative arthropathies
