Generation and specificity of a heteroantiserum to human peripheral blood monocytes

Abstract

An antiserum to human monocytes was raised in a rabbit by immunization with adherent mononuclear cells. After absorption with AB erythrocytes and an autologous B-cell line, the specificity of the antiserum was studied by complement-mediated lysis and direct fluorescence on a Fluorescence-Activated Cell Sorter (FACS). No reactivity was found with fresh B and T lymphocytes or T- and B-cell lines. More than 75% of adherent mononuclear cells were reactive with the antiserum. A mean of 26% of normal donors' peripheral blood mononuclear cells were labeled by direct immunofluorescence. Most of the large cells defined by light scatter profile on the FACS were stained by the antiserum but a fraction of cells of a smaller size was also positive. Morphologic and functional studies confirmed that the antiserum was specific for monocytes.