A POLYREACTIVE HUMAN ANTI-LIPID-A MONOCLONAL-ANTIBODY HAVING CROSS-REACTIVITY TO POLYSACCHARIDE PORTIONS OF PSEUDOMONAS-AERUGINOSA LIPOPOLYSACCHARIDES

A hybridoma cell line producing a human anti-lipid A monoclonal antibo dy (mAb), FKF-1F3 (IgM (kappa)) was obtained by cell fusion of Epstein -Barr virus-transformed cells and mouse myeloma. The mAb bound to not only Gram-negative bacterial lipid A, but also to polysaccharide porti ons of Pseudomonas aeruginosa lipopolysaccharides (LPS). The mAb seeme d to recognize two distinct regions of P. aeruginosa LPS other than li pid A, namely the outer core regions of some serotype strains and the O-polysaccharide region of serotype A strains. The mAb cross-reacted w ith N-acetyl-beta-glucosamine-conjugated bovine serum albumin, N-acety l-beta-galactosamine-conjugated bovine serum albumin, myosin and actin , but not with other autoantigens such as ss- and ds-DNA, cardiolipin and glycosaminoglycans. The mAb conferred protective activity against a mouse pseudomonal infection model. The evidence suggested that the m Ab was a naturally occurring polyspecific antibody that participated i n defense against pseudomonal infections.