Generation and characterization of a lipopolysaccharide-specific murine monoclonal antibody to Proteus vulgaris OX19

Abstract

The three strains of non-pathogenic Proteus species namely, Proteus vulgaris OX2, P. vulgaris OX19 and Proteus mirabilis OXK used in the Weil-Felix test are the group-specific cross-reactive antigens for Rickettsia and Orientia species. Earlier studies have revealed that the group specific and cross-reactive antigens responsible for the Weil-Felix test lie mostly in the lipopolysaccharide (LPS) moiety of the bacterial cell wall [Amano et al. (1993a) Infect Immun 61:4350-4355, (1993b) Microbiol Immunol 37:927-933, (1998) Infect Immun 66:923-926]. The three Proteus strains (OX2, OX19 and OXK) were used to raise murine monoclonal antibodies (MAbs) by hybridoma technology. Several MAb-producing hybridomas could be stabilized following limiting dilution. Affinity and specificity of these MAbs were checked by indirect ELISA using a battery of homologous and heterologous antigens including LPS. Amongst these, one MAb was found to be specific for P. vulgaris OX19 LPS. Since the Weil-Felix reaction is based on the cross-reactivity between the LPS based epitopes, this MAb could be of potential use in mapping of epitopes on the cross-reactive LPS and may also be useful as a potential diagnostic reagent.