CHARACTERIZATION OF CHLAMYDIA-PNEUMONIAE SPECIES-SPECIFIC PROTEINS IMMUNODOMINANT IN HUMANS

Proteins of Chlamydia pneumoniae immunodominant in humans were charact erized with the sera of 13 patients who were not likely to have been e xposed to C. trachomatis or C. psittaci. The serological responses amo ng these patients were similar on a qualitative basis, but some differ ences were found quantitatively. However, the serological responses of the patients who were infected with C. pneumoniae differed markedly f rom those of two patients who were infected with C. trachomatis and tw o who were infected with C. psittaci and those of mice that were trans tracheally infected with C. pneumoniae. Among proteins immunodominant in the patients who were infected with C. pneumoniae, a 40-kDa major o uter membrane protein was genus specific and 53-, 46-, and 43-kDa prot eins were species specific in their reactions with the majority of the human sera used. A few sera reacted Strongly with a 73-kDa protein ge nus specifically. Some proteins with weak immunogenicity exhibited spe cies specificity. An antigenic analysis with human sera and murine mon oclonal antibodies against the 53-kDa protein showed that the antigeni cities were strictly conserved among the seven strains of C. pneumonia e tested. The genus-specific 73-kDa protein was solubilized with octyl glucoside. All of the species-specific immunodominant proteins were so lubilized with sodium dodecyl sulfate, but the genus-specific major ou ter membrane protein was not. These results suggest that a serological diagnosis of C. pneumoniae infection could be achieved species specif ically by comparison of the serum responses to sodium dodecyl sulfate- and octylglucoside-soluble fractions.