Signal l From antigen ① CD40 B7. Q CD28 ② CD40 CD40L Signal 2 CD40 H C From th Signal 3 Cytokines From Th Activated B cell
Signal 2 Signal 1 From antigen From Th Signal 3 From Th
Antigen crosslinks mlg(BCR), generating signal 1, which increased expression of class lI MHC and costimulatory er eads to O Antigen-BCR complexes are internalized by receptor-mediated endocytosis and degraded to peptides, which are bound by class ll MHC and presented as peptide-MHC complexes Th cell recognizes ag -class lI MHc and b7-CD28 co-stimulation on b cell membrane which activates Th cell O Th cell begins to express CD40L Interaction of cD40 and cd40L provides signal 2 O Th cell release large quantities of cytokines(IL-4)signal 3 to support the progression of the B cell replication and differentiation
Antigen crosslinks mIg(BCR), generating signal 1, which leads to increased expression of class II MHC and costimulatory B7. Antigen–BCR complexes are internalized by receptor-mediated endocytosis and degraded to peptides, which are bound by class II MHC and presented as peptide–MHC complexes. Th cell recognizes Ag–class II MHC and B7-CD28 co-stimulation on Bcell membrane which activates TH cell. Th cell begins to express CD40L. Interaction of CD40 and CD40L provides signal 2. Th cell release large quantities of cytokines(IL-4) signal 3 to support the progression of the B cell replication and differentiation
Signal 3 B)A3。○ macrophages Th-secreting cytokines activation IL-1 Requlate B cell differentiation B Th IL-2 prolIteration IL-5 L-4 IL-6 differentiation IL-10 IFNy AFC AFC
Signal 3 Th-secreting cytokines Regulate B cell differentiation
B cells and humoral immune response 1. Recognition of the specific Ac g 2. Activation, proliferation, differentiation 1)2-signal activation 2)signal transduction 2. Germinal center later event 3. General feature of ab response
B cells and humoral immune response 1. Recognition of the specific Ag 2. Activation, proliferation, differentiation 1) 2-signal activation 2) signal transduction 2. Germinal center: later event 3. General feature of Ab response
Microbe Complement activation Bo ound C3d yrosine kinase phosphorylation cascade Recognition by b cells CR2 CD19 lg.lgβ CD81 Fyn Immunoreceptor Signals from Blk ->PTT tyrosine-based Ig and CR2 13-kinase activation motif complex PTK Src family (TAM B cell activation
PTK Src family immunoreceptor tyrosine-based activation motif (ITAM) Tyrosine kinase phosphorylation cascade