Characterisation of the effector cells in antibody-dependent and spontaneous cell-mediated cytotoxicity in swine against target cells infected with transmissible gastroenteritis virus

When porcine peripheral blood leucocytes were fractionated, lymphocytes were the most active effectors in both antibody-dependent cell-mediated cytotoxicity (ADCC) and spontaneous cell-mediated cytotoxicity (SCMC), although both polymorphs and macrophages showed some activity in ADCC. Adsorption of lymphocytes to antibody-sensitised or unsensitized PK-15-transmissible gastroenteritis (TGE) cells caused similar reductions in ADCC and SCMC effector activities. Over 60 per cent of the target-binding lymphocytes were non-specific esterase positive large lymphocytes, which did not form erythrocyte (E)-rosettes, and about 30 per cent were non-specific esterase positive medium sized lymphocytes, which formed low avidity E-rosettes. The remainder were non-specific esterase negative small lymphocytes, some of which formed high avidity E-rosettes. None of the eluted lymphocytes stained for surface immunoglobulin and all formed low avidity erythrocyte-antibody rosettes. Porcine killer and natural killer cells resembled in many respects those described in humans and rodents.