PHM 14: a novel monoclonal antibody that reacts with both normal and neoplastic human B cells but not B-CLL.

The reactivity of PHM 14, a monoclonal antibody to B cells produced in our laboratory was compared with Leu 10, a commercially produced antibody. Flow microfluorometric analysis showed that both PHM 14 and Leu 10 reacted with normal B cells, a variety of B cell lines and with B cell leukaemias and lymphomas, except in the case of B-CLL where PHM 14 reacted with a minority of cases, whereas Leu 10 reacted with a majority. PHM 14 and Leu 10 did not react with normal monocytes, granulocytes, T cells, T cell lines or with T cell leukaemias or lymphomas. Specificity of PHM 14 for B cells was further supported by the demonstration that PHM 14-positive blood cells, sorted from PHM 14-negative blood cells, reacted with polyclonal anti-immunoglobulins and with a panel of B cell markers but did not react with markers for T cells, monocytes, granulocytes or NK cells. Our results suggest that both PHM 14 and Leu 10 should be useful diagnostic reagents in the investigation of B cell-derived leukaemias and lymphomas.