Jon A. Rudbach

Cohn Changes in Serologic Reactivity of Endotoxin Induced by Fraction IV1 xof Normal Human Serum.

Summary A substantial loss in the ability of endotoxin to be precipitated by homologous antibody occurs following incubation with Fraction IV1 derived from normal human serum by cold ethanol fractionation. Evidence is presented that this loss in serologic reactivity is not associated with release of the major determinant sugar, per se. Rather, immunodiffusion analysis revealed the dispersion of a major antigen, with formation of a more rapidly migrating component. The latter was shown to form a line of identity with the O polysaccharide hapten.

Increased activation of antigen-primed or memory B cells by bacterial lipopolysaccharide

Treatment with bacterial lipopolysaccharide elicits the appearance of greater numbers of background antigen-specific plaque-forming cells (PFC) in the spleens of mice previously exposed or primed to subimmunogenic amounts of various non-cross-reacting antigens so as to generate detectable immunological memory. These findings suggest that treatment with lipopolysaccharide results in the activation of increased numbers of antigen-primed or memory B cells in mice previously exposed to antigen.