T-Dependent Activation带 EXtracellular pathogens Digested by macrophage--Ag complexed MHC class ii (present only in macrophage and few other cell types) Stimulates helper T cells(tH2) to find B cells, recognize particular peptide fragment ab Helper T cells(CD4+ cells; THi) produces FNv and activates macrophage BIOL 533 Lecture 7BIOL 533 3 Lecture 7 T-Dependent Activation • Extracellular pathogens – Digested by macrophage—Ag complexed MHC class II (present only in macrophage and few other cell types) – Stimulates helper T cells (TH2 ) to find B cells, recognize particular peptide fragment Ab – Helper T cells (CD4+ cells; TH1 ) produces IFN and activates macrophage