T and B Cell Activation

IP3

increases cytosolic Ca2+ concentration, activating phosphatase Calcineurin, thus activating NFAT.

MHC

Ag is endocytosed, processed + presented on .

L Selectin

binds to CD34 + GlyCAM- 1, slowing T cell down.

Macrophages

are anti- inflammatory, dont secrete inflammatory cytokines.

LFA

- 1 on T cell transiently binds to ICAM on dendritic.

CD45 tyrosine phosphatase

allows activation of receptor associated kinases.

Transcription factors

lead to the high- affinity α chain of IL- 2 receptor being expressed, along w. IL- 2.

Lck

phosphorylates ITAMs on cytoplasmic domains of CD3 + ζ chain.

CTLs

express FasL, which binds to Fas (of which expression is increased after inflammation /cell stress) induces nuclease to randomly cleave DNA.

Dendritic encounter

Ag through PAMPs and PRRs and become activated (mature)

ITAMs

Phosphorylated act as docking sites for protein kinase ZAP- 70.

CD19

: cytoplasmic tail is phosphorylated by Blk, Fyn Lyn plays role in additional activation signals.

TCR

If recognizes MHC: peptide, conformational changes in cell adhesion molecules occur to strengthen interactions + form T cell- dendritic cognate pair.

DAG

can activate Ras- induced signaling cascade, resulting in transcription factor AP- 1.

CR2

: recognizes complement, soluble or cell surface Ag.

Pinocytosis

: engulfing bulk phase fluid.

rapid proliferation

Autocrine action: cell makes IL- 2 which binds to IL- 2 receptor on its own surface signals to begin .

CD40L

on T cell binds CD40 on B cell to induce expression of genes needed for full activation of B cell drive clonal expansion.

Centroblasts

: rapidly proliferating B cells in center of germinal center; as they migrate toward outside, toward the FDCs, they become centrocytes (less rapidly proliferating B cells)

ZAP

- 70 initiates multiple signaling cascades, resulting in translocation of nuclear transcription factors (NF- κB, AP- 1, NFAT) to the nucleus where they induce expression of genes for T cell activation + proliferation.

co stimulatory molecule B7

Signal 2: is bound by CD28.

IL

- 4 activates mast cells; - 5 recruits eosinophils + promotes their survival; - 13 acts on goblet cells to produce more mucus.

T Cell enters

lymph node through high endothelial venule and goes to T cell area.

TFH

Once gives B cell survival signal, it undergoes isotype switching + proliferates.

LFA

- 1 + ICAM interaction is constitutively weak, but strengthens w. chemokine signaling to hold T cell strongly to HEV cell.

CTL

releases cytotoxic granules w. perforin + granzymes onto target cell surface; perforins form channels for granzymes to enter target cell + induce proteases to cleave DNA + induce apoptosis.

MHC

Signal 1: Dendritic presenting peptide on that is recognized by TCR and co- receptor (CD4 /CD8)