DETECTION OF EHRLICHIA-CHAFFEENSIS IN HUMAN TISSUE BY USING A SPECIES-SPECIFIC MONOCLONAL-ANTIBODY

A mouse monoclonal antibody (MAb 1A9) was produced and used in detecti on of Ehrlichia chaffeensis in human tissues including kidney, liver, and lung by using an indirect immunohistologic stain. MAb 1A9 was spec ific to E. chaffeensis and did not react with other bacteria, includin g Ehrlichia canis, which is the organism most closely related to E. ch affeensis. It reacted with an epitope present in two surface proteins of E. chaffeensis with molecular masses of 29 and 27 kDa. E. chaffeens is was easily detected in human tissue by immunohistology with MAb 1A9 . This study demonstrates that our MAb can provide a specific and simp le method for detection of E. chaffeensis in clinical specimens for es tablishing an etiologic diagnosis of human ehrlichiosis; it may also p rovide a tool for the investigation of immunopathologic characteristic s in infected patients.