BACTERIAL LIPOPOLYSACCHARIDE (LPS)-SPECIFIC ANTIBODIES IN COMMERCIAL HUMAN-IMMUNOGLOBULIN PREPARATIONS - SUPERIOR ANTIBODY CONTENT OF AN IGM-ENRICHED PRODUCT

The anti-LPS antibody content of commercial intravenous immunoglobulin s was examined by quantitative ELISA using LPS preparations from Esche richia coli, Klebsiella and Pseudomonas aeruginosa O serotypes occurri ng most frequently in Gram-negative septicaemia. Three IgG products fr om different manufacturers and one IgM-enriched product were tested. M ean antibody levels were significantly higher in the IgM fraction of t he IgM-enriched product compared with 'pure' IgG products, indicating that natural antibodies against bacterial LPS belong primarily to the IgM class. Immunoblotting studies showed that antibody specificities w ere directed mainly against O side chain epitopes. Antibodies against rough mutant LPS representing various chemotypes were detected in IgG but not in IgM products. The virtual absence of antibodies against Vib rio cholerae LPS indicated that human anti-LPS antibodies result from continuous environmental exposure to Gram-negative pathogens. These da ta support the further development of IgM-enriched preparations for pr ophylaxis and treatment of Gramnegative nosocomial infections.