Natural killer activity in the rat. II. Analysis of surface antigens on LGL by flow cytometry.

With the use of monoclonal antibodies and continuous flow microfluorometry, we have examined the cell surface antigenic characteristic of rat large granular lymphocytes (LGL) and compared them with monocytes, T cells, and polymorphonuclear leukocytes (PMN). The antigenic profile of rat LGL was of particular interest because these cells have been shown to be highly associated with natural killer (NK) activity. This analysis of enriched populations demonstrated that rat LGL are in antigenically distinct population of cells that share some characteristics with monocytes, T cells, and PMN. Essentially all of the cells in the enriched LGL population expressed with W3/13, OX-8, leukocyte-common (L-C), and asialo GM1 antigens. A portion of these cells were also positive with a monoclonal Ab against the ART-1a antigen. In contrast, few LGL expressed the Ia, W3/25, surface immunoglobulin (sIg), or Thy 1.1 antigens. Monocytes demonstrated a pattern of reactivity similar to LGL but were found to by OX-8 negative. As previously reported, a portion of the T cells were found to express ART-1a, W3/25, and/or OX-8. These results demonstrate that rat LGL are not typical T cells, B cells, monocytes, or PMN. However, the sharing of antigenic markers by LGL with some T cells and monocytes raises the possibility that LGL may be in the development lineage of 1 of these populations.