REGULATION OF THE ANTIBODY RESPONSE TO MICROBIAL POLYSACCHARIDE ANTIGENS

糖基化蛋白（GP），从滑翔细菌中分离

Glycosylated proteins (GP), isolated from the gliding bacterium Cytophaga johnsonae, possess several biological and immunological properties usually attributed to the lipopolysaccharides (LPS) or endotoxins of gram-negative bacteria. They are able to (a) activate 70Z/3 pre-B cells to synthesize IgM, (b) induce B cells from both LPS-responsive and LPS-defective strains of C3H mice to synthesize non-antigen-specific polyclonal immunoglobulin, (c) induce macrophages to produce tumor necrosis factor (TNF), and (d) modulate the magnitude of the antibody response in the absence of regulatory T cells. This occurs, despite the fact that GP are free of lipid A as well as 2-keto-3-deoxyoctonate, two components that are common to all preparations of bacterial LPS. The ability of lipid A derived from the nontoxic LPS of Rhodopseudomonas sphaeroides to block the ability of toxic LPS - but not GP - to induce TNF by macrophages, suggest that GP and LPS may be acting through different mechanisms and/or cell surface receptors to elicit the effects observed.