Studies on natural killer (NK) cells. I. NK cell specific antibodies in CE anti-CBA serum

An antiserum prepared by injecting CE mice with CBA spleen cells has been shown to contain antibodies specifically reactive with NK cells. The serum also contains antibodies detectable in C-dependent dye exclusion tests, but in a study of (CE X CBA)F1 X CE mice reactivity in this test was found to segregate independently of sensitivity of NK cells to inactivation. Moreover, abrogation of NK activity was observed with concentrations of antiserum and C that were considerably lower than those required for detectable cytotoxicity as measured by dye uptake. Thus, it is possible to use this antiserum for the selective removal of NK activity. Analysis of the strain distribution of NK cell sensitivity to CE anti-CBA serum suggests that this reagent may detect an allele of the NK-1 system, and we have tentatively designated the allelic product as NK-1.2, and the corresponding antibodies as anti-NK-1.2. However, the possibility that CE anti-CBA serum detects a new system of NK-specific antigen has not been excluded.