IMMUNOHISTOCHEMICAL DIAGNOSIS OF TYPHUS RICKETTSIOSES USING AN ANTILIPOPOLYSACCHARIDE MONOCLONAL-ANTIBODY

A monoclonal antibody directed against an epitope on the lipopolysacch aride of typhus-group rickettsiae was developed for the purpose of det ecting this heat-stable, proteinase-resistant antigen in formalin-fixe d, paraffin-embedded tissues. Rickettsia prowazekii organisms were ide ntified in endothelium and macrophages in sections of the brains of th ree Egyptian men who died of epidemic louse-borne typhus in Cairo duri ng World War II and in the brain from a recent case of typhus fever ac quired in Burundi. R. typhi organisms were identified in endothelial c ells from a fatal case of murine typhus and in experimentally infected mice. This approach is applicable not only to the study of archival t issues and experimental animal models but also could be used to establ ish a timely diagnosis of typhus-group rickettsiosis by immunohistoche mical examination of cutaneous biopsies of rash lesions during the acu te stage of illness.