Enzyme immunoassay of the antibody response to Brucella andYersinia enterocolitica09 infections in humans

Abstract

Summary: An enzyme immunoassay, with phenol–water-extracted lipopolysaccharide (LPS) fromBrucella abortusas antigen, was used to detect the class-specific antibody response in sera from 173 patients withB. abortus, B. melitensis or B. suisinfection. Sera from 30 patients with salmonellosis, yersiniosis or tularaemia and from 25 healthy individuals served as controls. TheB. abortusLPS antigen permitted a safe diagnosis of acute and chronic brucellosis with high IgM and rising IgG titres in sera collected in the acute stage of the disease, and with elevated IgG titres only in the chronic stage. TheB. abortusLPS antigen also permitted a specific diagnosis with the exception of the high titres estimated in sera from patients withYersinia enterocolitica09 infection. The problem with that well-known reciprocal cross-reactivity was overcome by using two additional antigens:Y. enterocolitica09 native and periodate oxidized and borohydride reduced LPS preparations. In sera from patients with brucellosis high titres were estimated against all three antigens, whereas in sera from patients with yersiniosis caused by serotype 09 high titres were measurable only with theB. abortusand theY. enterocoliticanative LPS antigens. These data suggest that theB. abortusandY. enterocolitica09 LPS share one antigenic determinant resistant to periodate oxidation and borohydride reduction, and that in addition theY. enterocolitica09 LPS has a determinant which is sensitive to periodate oxidation and borohydride reduction.