Skip to Content
Medical Term:

accessory molecules


Definition: surface receptors on immune cells, which participate in cell-cell interactions and modulate the immunologic outcome. For example, in T-cell recognition of B-cell presented–antigen, the primary interaction occurs through CD3-CD4 binding to MHC and antigen, but this interaction is amplified if concomitant accessory molecule binding also occurs, CD28 to B7.
