Endotoxin-binding and -neutralizing properties of recombinant bactericidal/permeability-increasing protein and monoclonal antibodies HA-1A and E5

• Published in: Critical care medicine Vol. 22; no. 4; p. 559
• Main Authors: Marra, M N, Thornton, M B, Snable, J L, Wilde, C G, Scott, R W
• Format: Journal Article
• Language: English
• Published: United States 01-04-1994
• Subjects: Animals; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - metabolism; Antimicrobial Cationic Peptides; Blood Proteins - immunology; Blood Proteins - metabolism; Endotoxins - immunology; Female; Humans; Lethal Dose 50; Lipopolysaccharides - metabolism; Membrane Proteins; Mice; Prospective Studies; Shock, Septic - metabolism
• ISSN: 0090-3493
• DOI: 10.1097/00003246-199404000-00009

To compare the endotoxin-binding and -neutralizing properties of bactericidal/permeability-increasing protein, the human monoclonal antiendotoxin antibody HA-1A, and the murine antiendotoxin antibody E5.
Prospective, randomized, placebo-controlled laboratory study.
Biotechnology company research laboratory.
Female CD-1 mice.
Recombinant bactericidal/permeability-increasing protein, HA-1A, a human immunoglobulin M monoclonal antibody raised against Escherichia coli J5 (Rc) endotoxin, and E5, a murine immunoglobulin M monoclonal antibody raised against E. coli J5 endotoxin, were compared in the following assays: a) binding to rough lipopolysaccharide immobilized onto microtiter plates; b) inhibition of lipopolysaccharide activity in the limulus amebocyte lysate assay; c) inhibition of lipopolysaccharide-induced cytokine release in whole blood; and d) protection against lethal endotoxin challenge in CD-1 mice.
The binding affinity of bactericidal/permeability-increasing protein for immobilized lipopolysaccharide is apparently greater than the binding affinity of HA-1A or E5. Bactericidal/permeability-increasing protein neutralized lipopolysaccharide activity in the chromogenic limulus amebocyte lysate assay, while neither monoclonal antibody inhibited lipopolysaccharide activity. Similarly, bactericidal/permeability-increasing protein reduced lipopolysaccharide-mediated tumor necrosis factor production in human whole blood in vitro, whereas monoclonal antibodies had slight (HA-1A) or no (E5) effect on lipopolysaccharide activity in this system. Administration of bactericidal/permeability-increasing protein gave > 90% protection against an LD60 dose of endotoxin in CD-1 mice, while treatment with HA-1A or E5 did not improve survival rate.
Neither monoclonal antibody was as effective as bactericidal/permeability-increasing protein at binding or neutralizing endotoxin in vitro or in vivo. The potent endotoxin-binding and -neutralizing properties of bactericidal/permeability-increasing protein indicate that it might be useful in the treatment of endotoxin-related disorders in humans.