Protective properties of a human IgG preparation rich in antibodies to a wide spectrum of lipopolysaccharides

Abstract

Naturally occurring human IgG, rich in antibodies to different lipopolysaccharides was investigated for possible protective effects against lethal endotoxin shock and lethal gram-negative infection in mice. The IgG preparation was obtained from pooled serum of selected blood donors with high concentrations of antibodies to 11 different LPS as measured by ELISA. The human IgG (5 mg/mouse) protected C3H/TifF mice against an otherwise lethal infection with Salmonella typhimurium. The human IgG also inhibited the lethality induced by purified LPS in D-galactosamine sensitized C57B1/6 mice. The protection was dependent on the IgG dose given. However, protection was not obtained against all the LPS preparations tested. Absorption of the IgG with different LPS, showed the protection to be caused by serotype-specific anti-LPS antibodies. Protection against a given LPS was not related directly to the corresponding anti-LPS titer as measured by ELISA and passive hemolysis. The interpretation of these results is discussed.