Antigenic relationships among the rickettsiae of the spotted fever and typhus groups.

Using immunoblots to analyze antigenic relationships among the pathogenic spotted fever and typhus group rickettsiae, I found that the rickettsial lipopolysaccharide (LPS) was a group-specific antigen. All the rickettsiae examined had 135-kDa and 58-kDa protein antigens. The spotted fever rickettsiae and Rickettsia canada had, in addition, 190-kDa protein antigens which were antigenic analogs of previously described protective antigens of R. conorii and R. rickettsii.