Expression of T-cell associated antigens by porcine natural killer cells.

We have examined the cell surface phenotype of porcine natural killer (NK) cells and compared them with classic porcine cytotoxic T lymphocytes (CTL). NK cells were susceptible to treatment with monoclonal antibodies to CD2 (PT11), CD8 (PT8) and Ia plus complement (C), as well as with antiserum to asialo-GM1 (ASGM1) plus C. In addition, monoclonal antibodies to leucocyte function antigen 1 (LFA-1) but not to CD8 blocked NK-mediated lysis in the absence of C. This is in contrast to porcine CTL, which were eliminated by antibodies to CD2, CD8 and Ia plus C, but not by anti-ASGMI plus C, and which were blocked by anti-CD8 in the absence of C. Therefore, although porcine NK cells are similar to porcine CTL, they are distinguished by several important differences.