How do helper T cells help B cells?

Activation of helper T cells by antigen presentation-Step 1

bacterium is taken up by phagocytosis and degraded in a lysosome

Activation of helper T cells by antigen presentation-Step 2

bacterial antigenic peptides are displayed on APC cell surface bound to class II MHC molecules and presented to helper(CD4+) T cells with TCRs

Activation of helper T cells by antigen presentation-Step 3

APC secretes cytokines that activate T cells

Activation of helper T cells by antigen presentation-Step 4

activated T cells secretes cytokines that stimulate T cells to proliferate to expand clone of selected cells

Activation of helper T cells by antigen presentation-Step 5

cloned helper T cells are ready to activate B cells and enhance other immune activities

Activation of B cells responsive to T-dependent antigens-Step 6

BCR binds to antigen, antigen is internalized by receptor-mediated endocytosis and its macromolecules degraded, antigenic peptides produced are displayed on cell surface bounded to class II MHC molecules

Activation of B cells responsive to T-dependent antigens-Step 7

TCR of a helper T cell recognizes specific antigen on B cell, and CD4 coreceptor links the two cells together

Activation of B cells responsive to T-dependent antigens-Step 8

helper T cell secretes cytokines that stimulate B cell proliferation to produce clone of selected cell

Activation of B cells responsive to T-dependent antigens-Step 9

some cloned B cells differentiate into plasma cell, which secrete antibodies specific for antigen, while few differentate into memory B cell

Activation of B cells responsive to T-dependent antigens-Step 10

antibodies bind with antigen, targeting antigenic invader for destruction by innate immune system