Lipopolysaccharides (LPS) of Oral Black-Pigmented Bacteria Induce Tumor Necrosis Factor Production by LPS-Refractory C3H/HeJ Macrophages in a Way Different from That of Salmonella LPS

Abstract

ABSTRACT Some lipopolysaccharide (LPS) preparations from S- or R-form members of the family Enterobacteriaceae and oral black-pigmented bacteria ( Porphyromonas gingivalis and Prevotella intermedia ) are known to activate LPS-refractory C3H/HeJ macrophages. When contaminating proteins are removed from R-form LPS of Enterobacteriaceae by repurification, however, this ability is lost. In the present study, we investigated the capacity of LPS from P. gingivalis , P. intermedia , Salmonella minnesota , and Salmonella abortusequi to induce production of tumor necrosis factor (TNF) in gamma interferon-primed C3H/HeJ macrophages before and after repurification. P. abortusequi S-LPS was fractionated by centrifugal partition chromatography into two LPS forms: SL-LPS, having homologous long O-polysaccharide chains, and SS-LPS having short oligosaccharide chains. Prior to repurification, all LPS forms except SL-LPS induced TNF production in both C3H/HeJ and C3H/HeN macrophages. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that repurification removed contaminating protein from the preparations, and repurified SS-LPS and S. minnesota Ra-LPS no longer stimulated TNF production in C3H/HeJ macrophages, although C3H/HeN macrophages remained responsive. In contrast, repurified oral bacterial LPS retained the capacity to induce TNF production in C3H/HeJ macrophages. Oral bacterial LPS preparations also were not antagonized by excess inactive, repurified SL-LPS; Ra-LPS; Rhodobacter sphaeroides lipid A, a competitive LPS antagonist, or paclitaxel, an LPS agonist, and they were comparatively resistant to polymyxin B treatment. Nevertheless, oral bacterial LPS was less toxic to d -galactosamine-treated C3H/HeN mice than was LPS from Salmonella . These findings indicate that the active molecule(s) and mode of action of LPS from P. gingivalis and P. intermedia are quite different from those of LPS from Salmonella .