Immunological studies on treponemal antigens. I. Isolation and characterization of an antigenic substance in the culture supernatant of avirulent T. pallidum (Nichols).

Several investigators have shown that the antigens of Treponema pallidum are tightly bound to organisms occurring in vivo (Eagle and Fleischman, 1948; McLeod and Magnuson, 1953; More recently Metzger, Mic- halska, Podwinska, and Smogor (1969) have found that the immunogenic properties of pathogenic T. pallidum are derived from their protein component. A serologically-active protein was isolated from a nonpathogenic strain by D'Alessandro and Dar- danoni (1953). This antigen was later proved to be related to the protein fraction of the pathogenic T. pallidum strain (Dardanoni and Censuales, 1957; Cannefax and Garson, 1959). We considered the possibility that the protein component of cultures of avirulent T. pallidum may be immunogenic and provide a ready source of antigen. The present study was performed with cultured T. pallidum (Nichols) and the supematant protein components were isolated and characterized for immunogenicity.