Murine monoclonal antibodies cross-reactive with feline peripheral blood mononuclear cells

Twelve murine monoclonal antibodies (MAB), specific for canine, human, and mouse cell surface determinants on lymphohemopoietic cells, were tested for reactivity (using indirect immunofluorescence) with peripheral blood mononuclear cells (PBMC) from 3 normal cats and 3 FeLV-positive cats with lymphoblastic leukemia. MAB DLy6 and 1H3, specific for canine lymphocytes, MAB HB57S, specific for human mu(IgM) chain, MAB J-118 40.164.3 and H81.98.71, specific for murine and human Ia, all had higher binding levels with PBMC from FeLV-positive cats compared to normal cats. Two MAB (S-78, S-24), specific for human class I determinants, cross-reacted with PBMC from both groups of cats. This panel of MAB may be useful for characterizing immunologically reactive cell subsets in normal as well as retrovirus-diseased animals.