Changes in lymphokine-activated killer activity in peripheral blood lymphocytes from canine transmissible venereal sarcoma models.

Time course changes in anti-tumor activity induced in peripheral blood lymphocytes (PBL) with recombinant human interleukin-2 (rhIL-2) and phytohemagglutinin-P (PHA) were studied in dogs implanted with canine transmissible venereal sarcoma (CTVS) as a tumor-bearing model. The rhIL-2-dependent and PHA-dependent cultures allowed selective proliferation of lymphocytes expressing Thy-1 antigens. The lymphocytes acquired a prolonged anti-tumor activity against the CTVS cells, starting from 2 weeks after the culture, indicating generation of lymphokine-activated killer (LAK) cells. The LAK cells showed serial growth in rhIL-2-containing culture medium for at least a further 2 weeks without loss of the anti-tumor activity.