[Two mesenchymal tumor cell lines for the determination of natural killer (NK) cell activity in the peripheral blood of dogs].

The two mesenchymal cell lines K1 and K6 were established from round cell tumours located at the lips of two dogs. Both cell lines were characterized as being of myelomonocytic origin by morphological, cytochemical, immunocytochemical and functional criteria. In the 51chromium release assay (effector/target cell ratio 100/1) the K6-cell line revealed a mean cytotoxic sensitivity of 53.6% and thus showed a susceptibility similar to that of the epithelial CTAC line (57.8%). The K1-cell line exhibited less cytotoxic activity (41%) when incubated for 14 h, but showed results comparable to the K6-cell line, when the incubation time was reduced to 8 h.