The in vivo activity of human immunoglobulin M monoclonal antibody IN-2A8, which is specific for flagellum type b ofPseudomonas aeruginosa, was evaluated in comparison to anti-O antigen (serotype B) MAb KO-2F2 and in combination with antibiotics. IN-2A8 showed stronger activity than KO-2F2 against subcutaneous infection in burned mice, while it was much less active against intraperitoneal infection in normal mice. In a burn infection model, IN-2A8 inhibited the increase of bacteria in skin lesions weakly and that in blood significantly, suggesting that it strongly suppressed bacterial spread to blood. The activity of IN-2A8 in combination with 10 antipseudomonal antibiotics against intraperitoneal infection was examined. Clear additive effect was observed with a combination of either carbapenem or aminoglycoside antibiotics in terms of mouse survival. The administration of an antibiotic, imipenem-cilastatin, simultaneously with or before that of IN-2A8 gave a combined effect, but the reverse order did not. The combination of IN-2A8 with imipenem-cilastatin decreased numbers of viable bacteria in the peritoneal cavity and blood and kept them low for a longer time than did either treatment alone. These results suggest that an antiflageUar monoclonal antibody would be effective against systemic infection in combination with some kinds of antibiotics.
The protective activity against experimental Pseudomonas aeruginosa infection of a human monoclonal antibody, MH-4H7, which is thought to recognize L-rhamnose and its neighboring residues in the outer core region of P. aeruginosa lipopolysaccharide and which binds to strains of Homma serotypes A, F, G, H, K, and M, was studied in normal, burned, and leukopenic mice. MH-4H7 at doses of 0.1 to 1.0 micrograms per mouse (5 to 50 micrograms/kg) was effective against serotype A, F, G, H, and K clinical isolates of P. aeruginosa tested in normal mice but not against strains of serotype M, B, E, or I. The 50% protective doses were calculated to be 0.01 and 0.1 micrograms per mouse against challenge with serotype G strains and 3 to 8 micrograms per mouse against challenge with serotype A strains. MH-4H7 promoted macrophage-mediated opsonophagocytosis of serotype A, F, G, H, and K strains but not of serotype M strains. The opsonophagocytic activity, expressed as the reduction rate of viable bacteria in the presence of MH-4H7, macrophages, and complement, was higher against serotype G strains (more than 90%) than against serotype A strains (60 to 80%) and serotype F, H, and K strains (50 to 86%). It was correlated with the protective activity but not with the binding intensity of MH-4H7 to the organisms. In addition, burned and leukopenic mice as well as normal mice infected with serotype G strains recovered from a very low dosage of MH-4H7. Thus, a monoclonal antibody directed to the outer core region of P. aeruginosa lipopolysaccharide was effective against infection with a wide range of O-serotype strains of P. aeruginosa.
Three stable hybridoma cell lines, IN-2A8, IN-5D6, and ZI-3A8, that secrete human monoclonal antibodies (MAbs) specific for b-type flagella of Pseudomonas aeruginosa were established by fusing peripheral blood lymphocytes from healthy volunteers with murine myeloma P3X63-Ag8.653 cells. The immunoglobulin M MAbs reacted specifically with flagellin (Mr, 52,000) by Western blotting (immunoblotting) analysis and bound specifically to clinical isolates belonging to Homma serotypes A, B, H, I, and M at frequencies of 58, 50, 46, 30, and 35%, respectively, but did not bind to any serotype E or G isolates. Overall, the MAbs bound to 31% of the clinical isolates. MAb IN-2A8 strongly protected burned mice challenged with P. aeruginosa bearing b-type flagella from death following parenteral administration of 0.1 ,ug per mouse. This MAb also inhibited P. aeruginosa colony spreading in soft agar at a concentration of more than 1 ,ug/ml but only slightly enhanced opsonophagocytosis by human polymorphonuclear leukocytes. A line of evidence suggests that the potent in vivo activity of MAb IN-2A8 in the burned-mouse model is likely to be caused by its inhibition of bacterial motility after binding to flagella.
We have established a human -mouse heterohybridoma cell line producing a human monoclonal antibody TS-3G2 (IgGyl,K). This monoclonal antibody specifically bound to 0-polysaccharides belonging to plural Pseudomonas aeruginosa Homma serotypes, A and H, in contrast to serotype-specific monoclonal antibody which exclusively bound to strains belonging to a single specific serotype. The binding affinity for serotype A strains was higher than that for serotype H strains. Competitive eniyme immunoassay experiments with 0-polysaccharide preparations derived from IID 1001, NCTC 8505 (serotype A) and IID 1009 (serotype H) and their derivatives demonstrated that the N-acetyl-L-galactosaminuronic acid residue in 0-polysaccharide was essentially involved in the epitope for TS-3G2. Furthermore, a 6-deoxy-hexosamine residue neighboring the reducing terminal of Nacetyl-L-galactosaminuronic acid residues was also concerned with the epitope to some extent. In the experimental infection model of normal mice, the monoclonal antibody TS-3G2 showed a protective activity against both strains of serotype A and H.Pseudomonas aeruginosa is a major pathogen for opportunistic infections in immunosuppressed and immunocompromised hosts such as patients of cancer, burn, cystic fibrosis, and diffused panbronchiolitis. The efficacy of chemotherapy against P. aeruginosa infections is diminished due to its insensitivity and resistance to many antibiotics and the weakened defense mechanisms of patients [l, 21. Therefore, immunotherapy of active immunization with vaccines or passive immunization with immunoglobulin preparations is an alternative for the treatment of infections with P. aeruginosa. Among various cell-surface components, 0-polysaccharide (0-antigen) in lipopolysaccharide (LPS) was reported to be the most potent immunogens. In fact, serotype-(0-antigen)-specific human monoclonal antibodies (mAbs) were demonstrated to be protective against P. aeruginosa infections in mouse models [3 - The structure of P. aeruginosa 0-polysaccharide is very complicated. It contains unknown rare components and the detailed structure is somewhat different between strains, even in a classified serotype. In recent years, extensive studies on the chemical structure of 0-polysaccharide have been carriedCorrespondence to H. Noguchi, Laboratory of Biotechnology, Takarazuka Research Center, Sumitomo Chemical Co., Ltd, 4-2-1, Takatsukasa, Takarazuka, Hyogo 665, JapanAbbreviations. mAb, monoclonal antibody; LPS, lipopolysaccharide; GalNAcA, N-acetylgalactosaminuronic acid; Bac(NAc),, 2,4-di-N-acetylbacillosamine; Bac2NBtOH4NAc, 2-N-(3-hydroxybutanoyl)-4-N-acetylbacillosamine; QuiNAc, N-acetylquinovosamine; Rha, rhamnose; IATS, international antigen typing scheme; CFU, colony forming units. out and the typical structure for the standard strains of each serotype has been disclosed [12]. Many kinds of rare aminouronic acids have been found as a component of 0-polysacchdride in P. aeruginosa. In nature, L-galactosaminuronic acid had been only found in 0-polysaccharide o...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.