Detection and characterization of natural killer cells in Syrian golden hamsters

Natural killer (NK) cell activity was observed in the peripheral blood and spleen of 8- to 10-week-old Syrian golden hamsters, but not in the bone marrow or thymus. Low, but significant, levels of cytotoxicity were also observed in mesenteric and axillary lymph nodes and cells harvested from the peritoneum. Cytotoxicity, in a 4-hr 51Cr-release assay, was found to be nylon wool non-adherent and was significantly reduced by treatment with trypsin or incubation at 37 degrees C for 18 hr. Natural cytotoxicity was shown to be low at 1 week of age, but increased to a maximum at 8 weeks and was maintained into old age. Correlation was observed between peripheral blood cytotoxicity and the presence of large, often granular, lymphocytes following fractionation of effector cells by Percoll discontinuous gradient separation. These findings are compared with previous studies in hamsters, where the results of longer-term cytotoxicity tests differ in some respects to those of the present study.