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


METHODS
Prospective, randomized, placebo-controlled laboratory study.


METHODS
Biotechnology company research laboratory.


METHODS
Female CD-1 mice.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Marra
M N
MN
Incyte Pharmaceuticals, Palo Alto, CA 94034.
Thornton
M B
MB
Snable
J L
JL
Wilde
C G
CG
Scott
R W
RW
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism*; D061067:Antibodies, Monoclonal, Humanized; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins / Q000276:immunology / Q000378:metabolism*; D004731:Endotoxins / Q000276:immunology*; D005260:Female; D006801:Humans; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000378:metabolism; D008565:Membrane Proteins; D051379:Mice; D011446:Prospective Studies; D012772:Shock, Septic / Q000378:metabolism
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D004731:Endotoxins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C021623:bactericidal permeability increasing protein; C068069:nebacumab