A subset of normal human B lymphocytes expresses an antigen cross-reactive with gp52 of murine mammary tumor virus.

Three monoclonal antibodies (MAbs), VE7, VIG3, and IXF9, that detect the 52-kd glycoprotein (gp52) of murine mammary tumor virus (MMTV) were tested for reactivity on normal human tonsillar lymphoid cells in an indirect immunofluorescence assay. Two of the MAbs, VE7 and VIG3, reacted with subpopulations of B cells, whereas the third MAb, IXF9, showed only very low-level reactivity with human lymphoid cells. VE7 and VIG3 also reacted with small populations of peripheral blood lymphocytes, and all three MAbs reacted with some transformed human cell lines. The data suggest that subpopulations of normal human lymphocytes express antigens that are cross-reactive with the MMTV gp52, although not all of the viral gp52 epitopes are expressed on the surface of these cells.