Abstract
Chlamydia trachomatis proteins were electrophoresed and then transferred to nitrocellulose paper to detect chlamydial proteins which bind to eucaryotic cell membranes. Resolved polypeptides of C. trachomatis serovars J and L2 were reacted with iodinated HeLa cell membranes and autoradiographed. Infectious elementary bodies of both serovars possess 31,000- and 18,000-dalton proteins which bind to HeLa cells. In contrast, noninfectious reticulate bodies do not possess eucaryotic cell-binding proteins. Both proteins are antigenic when reacted with hyperimmune rabbit antisera in immunoblots and antisera raised against the 31,000- and 18,000-dalton proteins are inhibitory to chlamydia-host cell association. In addition, these antisera exhibit neutralizing activity. Our data suggest that these putative chlamydial adhesins play a key role in the early steps of chlamydia-host cell interaction and that antibody directed against them may be protective.