Monoclonal antibodies (MAbs) were generated against human CD16 (Fc gamma RIII) by fusion of NS1 myeloma cells with spleen cells from BALB/c mice immunized with synthetic peptide sequences derived from the CD16 genes. After screening, four hybridomas secreting MAbs (2 IgM and 2 IgG) were selected, cloned and characterized for their activity against CD16 by ELISA test, flow cytometry, rosette inhibition and immuno-blotting. MAbs reacted strongly in ELISA with a soluble form of CD16 (sCD16) present in human serum and to a lesser degree with soluble recombinant CD16 (srCD16). The binding characteristics of the four antibodies to the sCD16 were different, implying that the antibodies recognize different CD16 epitopes. FACS analysis of peripheral blood from healthy volunteers demonstrated that these MAbs are highly reactive with membrane CD16 of neutrophils cells (70-95%) and with a subset of lymphocytes (6-14%). These MAbs seem interesting and may lead to the purification of the soluble human CD16 and to the knowledge of its functions, its physiological role and the cellular polymorphism.