Gram-negative bacteria are common pathogens of man. Gram-negative sepsis is the most serious consequence of infections caused by these bacteria. Lipopolysaccharides (LPS), or endotoxins, are an essential component of the outer cell membrane of all Gram-negative bacteria and play a central pathogenic role in Gram-negative sepsis. The core region of endotoxin, which contains the lipid A moiety, is structurally and antigenically conserved among many Gram-negative bacteria. Lipid A mediates most biological activities important in pathogenesis. The goal of this proposal is to test the hypothesis that antibodies directed toward shared LPS core determinants cross-react broadly among heterologous LPS's, exhibit anti-endotoxic activity, and provide a protective function in septicemic infections due to diverse Gram-negative pathogens. Specific murine and human monoclonal antibodies (mAbs) will be prepared against the exposed core glycolipids of rough mutant Gram-negative bacteria. These mAbs will be evaluated in binding and immunoblotting assays for cross-reactivity with heterologous LPS's. Specific core epitopes recognized by mAbs will be identified in direct binding and competition studies employing LPS subcomponents, lipid A precursors, and synthetic lipid A analogs. The avidity with which mAbs bind to these ipitopes will be measured by solid-phase radioimmunoassay. The ability of core-specific mAbs to recognize antigenic target sites on the bacterial surface will be evaluated using whole bacterial cell assays, and the possible antibacterial activities mediated by such interactions will be determined. The blocking or neutralizing effect of core-specific mAbs on in vitro functional properties of homologous and heterologous LPS will be assessed. The in vivo inhibitory action of core-specific mAbs on LPS-induced shock and death will be evaluated, and therapeutic activity tested in animal models of Gram-negative sepsis. It is anticipated that these studies will: 1) Further elucidate the concept of cross-protective, anti-endotoxic immunity, 2) Define the therapeutic role of core-specific mAbs in Gram-negative sepsis, and 3) Provide fundamental new insights concerning the immunopathogenic role of LPS at the molecular level.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
Project #
Application #
Study Section
Bacteriology and Mycology Subcommittee 1 (BM)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Henry M. Jackson Fdn for the Adv Mil/Med
United States
Zip Code
Pollack, M; Ohl, C A; Golenbock, D T et al. (1997) Dual effects of LPS antibodies on cellular uptake of LPS and LPS-induced proinflammatory functions. J Immunol 159:3519-30
Pollack, M; Espinoza, A M; Guelde, G et al. (1995) Lipopolysaccharide (LPS)-specific monoclonal antibodies regulate LPS uptake and LPS-induced tumor necrosis factor-alpha responses by human monocytes. J Infect Dis 172:794-804
Pollack, M; Koles, N L; Preston, M J et al. (1995) Functional properties of isotype-switched immunoglobulin M (IgM) and IgG monoclonal antibodies to Pseudomonas aeruginosa lipopolysaccharide. Infect Immun 63:4481-8
Hoffman, W D; Pollack, M; Banks, S M et al. (1994) Distinct functional activities in canine septic shock of monoclonal antibodies specific for the O polysaccharide and core regions of Escherichia coli lipopolysaccharide. J Infect Dis 169:553-61
Pier, G B; Koles, N L; Meluleni, G et al. (1994) Specificity and function of murine monoclonal antibodies and immunization-induced human polyclonal antibodies to lipopolysaccharide subtypes of Pseudomonas aeruginosa serogroup 06. Infect Immun 62:1137-43
Evans, M E; Pollack, M (1993) Effect of antibiotic class and concentration on the release of lipopolysaccharide from Escherichia coli. J Infect Dis 167:1336-43
Field, S; Pollack, M; Morrison, D C (1993) Development of an anti-idiotype monoclonal antibody mimicking the structure of lipopolysaccharide (LPS) inner-core determinants. Microb Pathog 15:103-20
Siegel, S A; Evans, M E; Pollack, M et al. (1993) Antibiotics enhance binding by human lipid A-reactive monoclonal antibody HA-1A to smooth gram-negative bacteria. Infect Immun 61:512-9
Evans, M E; Pollack, M; Koles, N L et al. (1992) Lipopolysaccharide heterogeneity in Escherichia coli J5 variants: analysis by flow cytometry. J Infect Dis 166:803-11
Oishi, K; Koles, N L; Guelde, G et al. (1992) Antibacterial and protective properties of monoclonal antibodies reactive with Escherichia coli O111:B4 lipopolysaccharide: relation to antibody isotype and complement-fixing activity. J Infect Dis 165:34-45

Showing the most recent 10 out of 17 publications