NCIt definition : A humanized, non-Fc receptor (FcR)-binding IgG2 monoclonal antibody (MoAb) directed
against CD3 with potential immunosuppressive activity. Visilizumab binds to invariant
CD3 epsilon, one of the non-covalently-associated subunits of T-cell receptors (TCRs)
on activated T-cells. Upon binding to the TCR/CD3 complex, visilizumab induces apoptosis,
which may result in the selective clonal deletion of activated pathogenic T-cells.
This MoAb is engineered with a substitution at amino acid residues 234 and 237 (Val3Ala)
within the IgG2 Fc arm, rendering it unable to bind to type II FcRs; accordingly,
this agent is less likely to activate type II FcR-expressing resting T-cells.;
Alternative definition : NCI-GLOSS: A monoclonal antibody that binds to CD3 (a substance found on T-cells)
and that is being studied as a treatment for graft-versus-host disease (GVHD). It
belongs to the family of drugs called monoclonal antibodies.;