Human monoclonal antibodies that protect mice against challenge with Pseudomonas aeruginosa.

Lymphocytes from healthy volunteers and from cystic fibrosis patients were transformed with Epstein-Barr virus and cultured at a limiting dilution to generate lymphoblastoid cell lines that secreted human monoclonal antibodies specific for lipopolysaccharide (LPS) from Pseudomonas aeruginosa. Three cell lines (RM5, FDD7, and 11F9) produced immunoglobulin M (IgM) antibody species that reacted specifically with P. aeruginosa Fisher immunotypes 2, 4, and 5, respectively, and with LPS extracted from these immunotypes. A fourth cell line (9H10) produced a single IgM antibody species that recognized P. aeruginosa immunotypes 3, 6, and 7 and LPS extracted from them. Monoclonal antibodies secreted by cell lines RM5, FDD7, and 11F9 protected neutropenic mice prophylactically against challenge with P. aeruginosa immunotypes 2, 4, and 5, and those secreted by 9H10 protected against P. aeruginosa immunotypes 3 and 6 but did not protect against immunotype 7. In vivo experiments indicated that antibodies protected mice against infection by increasing the rate of bacterial clearance.