THE O-CHAIN OF BRUCELLA-ABORTUS LIPOPOLYSACCHARIDE INDUCES SDS-RESISTANT MHC CLASS-II MOLECULES IN MOUSE B-CELLS

LPS is the most important antigen of Brucella bacteria which are gram-negative facultative intracellular pathogens infecting a large proportion of animals and humans in the world. In order to get insights into the immune response mechanisms monitored by Brucella, its LPS was used as a model antigen. S-LPS, R-LPS, lipid A and O-chain purified from Brucella abortus were tested in their capacity of inducing SDS-resistant MHC class II molecules after incubation with murine B lymphoma cells. S-LPS and O-chain gave a significant response sugesting that O-chain might induce an association with class II itself or might act as a carrier for antigens to bind MHC class I-I molecules. (C) 1994 Academic Press, Inc.