Figure 3

Mechanisms of anti-idiotypic antibodies on B (B) and T cell (T) interaction. (A): B cells recognize antigen by membrane-expressed immunoglobulins (mIg) and receive bystander help from T-helper cells. (B) Alternatively, an anti-id may bind to mIg of a B-cell. This leads to processing and MHCII display of an anti-idiotypic peptide rendering T cell activation and help. (C) Because of idiotypic similarities between B and T cell receptors, an anti-idiotypic antibody may also force cooperation between B and T cells by binding to both. (D) Inhibition of B cell proliferation is achieved by simultaneous binding of the anti-id to its corresponding idiotype on mIg and via its Fcγ domain to FcγRIIb on the B-cell.