CELL-SURFACE PHENOTYPE OF 2 CLONED POPULATIONS OF BOVINE LYMPHOCYTES DISPLAYING NONSPECIFIC CYTOTOXIC ACTIVITY

Monoclonal antibodies specific for T cell differentiation antigens were tested on four cloned populations of lymphocytes derived from the peripheral blood mononuclear cells of an animal immunised with Theileria parva. The clones were defined functionally in terms of cytotoxic activity, MHC restriction and expression of messenger RNA for CD3 and T cell receptor (TCR). Two clones contained RNA transcripts for CD3, TCR-alpha and beta and were positive for CD2, CD5 and CD6; one of these was a typical CD4+ class II MHC-restricted non-cytotoxic clone while the other was a CD8+ class I MHC-restricted cytotoxic clone. By contrast, the remaining two clones had the characteristics of non-specific killer cells in that they exhibited moderate levels of non-MHC-restricted killing; they contained TCR-delta mRNA and a 1.2 kb truncated form of TCR-beta message, but they did not contain CD3 or TCR-alpha mRNA. One of these non-specific killer clones only expressed CD2 whereas the other clone only expressed CD8, but without the CD8 determinant recognised by monoclonal antibodies CC58 and BAT52. All four clones were negative for the WC1 antigen which is expressed on gamma/delta T lymphocytes.status: publishe