Heterogeneity of the L-rhamnose residue in the outer core of Pseudomonas aeruginosa lipopolysaccharide, characterized by using human monoclonal antibodies.

Hybridoma cell lines producing human monoclonal antibodies (MAbs) MH-4H7 and KN-2B11 [immunoglobulin M (lambda)] which bound to the outer core region of Pseudomonas aeruginosa lipopolysaccharide (LPS) were established by cell fusion of human peripheral lymphocytes with human-mouse heteromyeloma SHM D-33. Both binding specificity experiments with a series of LPS-defective mutants derived from P. aeruginosa PAC1R (P. S. N. Rowe and P. M. Meadow, Eur. J. Biochem.132:329-337, 1983) and competitive enzyme immunoassay experiments with monosaccharides demonstrated that alpha-L-rhamnose residues in the outer core of LPS might be in part an epitope. The MAbs specifically bound to clinical isolates belonging to Homma serotypes A, F, G, and K at a frequency of 70 to 86% and to serotypes H and M isolates at about 50%. They did not bind to any isolates of serotype B, E, and I tested. This evidence indicates that L-rhamnose and probably its neighboring residues in the other core of P. aeruginosa are heterogeneous in some association with the O serotype.