IDENTIFICATION OF DUCK T-LYMPHOCYTES USING AN ANTI-HUMAN T-CELL (CD3)ANTISERUM

Duck lymphocytes have not been classified into cells resembling B or T cells of mammals, Reagents used in the past to identify lymphocyte po pulations in other species pave not been useful for this purpose and a ntibodies raised to duck immunoglobulin bind in high proportions to bl ood and organ lymphocytes of ducks as well as to their red blood cells . Here we report that a polyclonal rabbit antiserum reacting to the CD 3 marker on human T cells has been used to identify duck T lymphocytes . These antibodies react with the intracytoplasmic portion of the huma n CD3 epsilon chain (amino acids 156-168), an epitope highly conserved between mammals. Immunohistochemical staining with this antiserum of sections of duck lymphoid organs and FACScan analysis of duck lymphoid cell suspensions identified a population of duck lymphocytes with a s taining pattern similar to that seen for mammalian T cells. This anti- human CD3 immunoprecipitated a 23 kDa protein from a duck lymphoblast lysate: a size similar to the human CD3 epsilon chain. This is the fir st direct identification of duck T lymphocytes.