Monoclonal antibodies that identify the CD3 molecules expressed specifically at the surface of porcineγδ-T cells.

The CD3 antigen is a surface structure associated with the T-cell receptor (TCR) to form a complex involved in antigen recognition and signal transduction. Reports on the structures of the CD3 molecules associated withαβ- andγδ-TCR have been contradictory. To investigate this issue, we raised a panel of monoclonal antibodies (mAb) against purified porcine CD3 molecules. Unlike the conventional anti-CD3, these mAb reacted specifically with peripheralγδ-T cells, but not withαβ-T cells. Immunoprecipitation showed that the antibody recognized a subset of CD3 molecules that were associated withγδ-TCR. Also unlike the conventional anti-CD3, these mAb, though directed at two different epitope groups, failed to induce antigenic modulation, T-cell proliferation and CD3-redirected cytotoxicity. Taken together, these results suggest that there are differences in the antigenicity, signal transduction potentials and probably structural differences between the CD3 molecules expressed at the surface ofαβ- andγδ-T cells. [ABSTRACT FROM AUTHOR]