Production of a monoclonal allo-antibody to murine natural cytotoxic cells.

A mouse IgG1 monoclonal antibody (1C4), which recognizes a cell surface molecule on murine natural cytotoxic (NC) cells was produced. By flow cytometry, 1C4 preferentially reacted with less than 5% of fresh CBA spleen cells and 20-50% of CBA-interleukin-3 (IL-3) cells, an in vitro derived NC-like cell line. In vitro treatment of spleen cells from a number of inbred mouse strains either with 1C4 alone or 1C4 coupled to dynabeads markedly decreased or abolished NC activity of the cells against 51Cr-labelled WEH1-164 targets. Splenic NC activity of these same mouse strains was also reduced or abolished by in vivo administration of 1C4. The effect was evident within 2 h of treatment and persisted for at least 1 week. In contrast 1C4 had little or no effect on splenic NK activity against 51Cr-labelled YAC-1 targets over the same range of experiments in vitro and in vivo. Results of strain surveys for both in vitro and in vivo reduction of splenic NC activity by 1C4 treatment showed that CBA, C57BL/6, BALB/c and NZB mice were positive and CE and DBA/2 mice were negative, indicating that 1C4 recognizes an allo-antigen on mouse NC cells. This allo-antibody has been designated NC-1.1, and thus 1C4 is an anti-NC-1.1 monoclonal antibody.