Preparation (M1) of monoclonal antibodies (MAb) that activate effector cells expressing Fcgamma RIII (A). Preparation (M1) of monoclonal antibodies (MAb) that activate effector cells expressing Fcgamma RIII (A). Monoclonal antibodies expressed from different clones, derived from selected hybridomas (especially heterohybridomas) or animal or human cells transfected with a vector containing a gene for an antibody, are purified, then incubated with a mixture containing target cells, effector cells expressing (A), and polyvalent immunoglobulin G (IgG). Those MAb that produce significant lysis of target cells (by induction of (A)-type antibody-dependent cellular cytotoxicity (ADCC)) are chosen. Independent claims are also included for the following: (1) MAb produced by (M1), having type-(A) ADCC over 60%, especially 90% of that for reference polyclonal antibodies； (2) any MAb directed against a particular antigen and able to activate effector cells to provide type-(A) ADCC over 60, especially 90% of that for reference polyclonal antibodies； (3) MAb that have, on the glycosylation site at Asn297 of Fcgamma , two-branched glycosylation structures with short arms, low degree of silylation and terminal mannose residues and/or non-intercalating N-acetylglucosamine (GlcNAc)； (4) cells that produce MAb； (5) pharmaceutical composition containing MAb； and (6) diagnostic composition containing MAb. ACTIVITY : Antibacterial； antiviral； cytostatic； hemostatic； immunostimulant. MECHANISM OF ACTION : Antibody-dependent cellular cytotoxicity inducer.
