For example, on introduction of antigen 5 (Ag5) into a person, more than 10 B cells have the opportunity to interact with it. Only a very few B cells(e.g. B5)have receptors specific for this antigen b5 binds ag5, internalizes, and processes and presents it on MHc class ll molecules on the surface of this b cell
For example, on introduction of antigen 5 (Ag5) into a person , more than 106 B cells have the opportunity to interact with it. Only a very few B cells (e.g. B5) have receptors specific for this antigen. B5 binds Ag5, internalizes, and processes and presents it on MHC class II molecules on the surface of this B cell
T helper cells with specific receptors for a peptide from Ag5 in mhc class ll bind to this complex and stimulate this b cell to clonally expand and differentiate into memory B cells and plasma cells which produce soluble antibody to Ag5. In addition direct t cell interaction with the b cell induces class switching, which depending on the type of helper cell (Th 1 vS Th2)and the cytokines it secretes, will result in production of antibody of the IgG, IgA or igE classes
T helper cells with specific receptors for a peptide from Ag5 in MHC class II bind to this complex and stimulate this B cell to clonally expand and differentiate into memory B cells and plasma cells which produce soluble antibody to Ag5. In addition, direct T cell interaction with the B cell induces class switching, which depending on the type of helper cell (Th1 vs Th2) and the cytokines it secretes, will result in production of antibody of the IgG, IgA or IgE classes
胸腺依赖性抗原(TD-Ag) 抗原 提呈的 02 抗原多肽 R BC 20 CD28 CKR B7 ack B CKR B细胞活化的双信号示意图
B细胞 ICAM-1 LFA-1 Th细胞 B7 D28 活化信号② 抗原 MHcⅡ类分子TCRa Th活化 BCR抗原加工、提呈 活化信号① CD4 CD40 CD40L B细胞活化 ICAM-1 LFA-1 CKR CK B细胞与Th细胞间相互作用
B cell signaling T cell signaling of the t cell of the b cell B7 CD28 CD40 CD40L Cytokine receptors L.yoking B cell growth and differentiation T cell growth and differentiation Reciprocal activation of T and B cells
B cell growth and differentiation T cell growth and differentiation Reciprocal activation of T and B cells