EIA WITH SPECIES-SPECIFIC MONOCLONAL-ANTIBODIES - A NOVEL SEROEPIDEMIOLOGIC TOOL FOR DETERMINATION OF THE ETIOLOGIC AGENT OF SPOTTED-FEVER RICKETTSIOSIS

All currently available assays for antibodies to the etiologic agents of spotted fever group rickettsioses detect reactivity with antigens o f lipopolysaccharides and the major cell wall proteins, which contain epitopes that are shared among many spotted fever group rickettsiae. T he hypothesis of this study was that a monoclonal antibody to a specie s-specific epitope of Rickettsia rickettsii would be blocked from bind ing to the rickettsial surface if the rickettsiae were incubated previ ously with serum containing species-specific antibodies to the epitope . In an EIA, binding of monoclonal antibody 5C10-F3 to R. rickettsii w as blocked by convalescent sera from patients with Rocky Mountain spot ted fever but not from those with Mediterranean spotted fever, endemic typhus, or Q fever or normal subjects. This assay should be useful in determining the origin of the high seroprevalence of spotted fever ri ckettsial antibodies in certain geographic regions and establishing a species-specific diagnosis in patients with undetermined rickettsial e xposure.