Identification of two novel genes encoding 97- to 99-kilodalton outer membrane proteins of Chlamydia pneumoniae

Two genes encoding 97- to 99-kDa Chlamydia pneumoniae VR1310 outer membrane proteins (Omp4 and Omp5) with mutual similarity were cloned and sequenced. The proteins were shown to be constituents of the C. pneumoniae outer memb rane complex, and the deduced amino acid sequences were similar to those of putative outer membrane proteins encoded by the Chlamydia psittaci and Chl amydia trachomatis gene families, By use of a monospecific polyclonal antib ody against purified recombinant Omp4, it was shown that without heating, t he protein migrated at 65 to 75 kDa in sodium dodecyl sulfate-polyacrylamid e gel electrophoresis, Immunoelectron microscopy showed that epitopes of Om p4 were exposed on the surface of C, pneumoniae elementary bodies, reticula te bodies, and outer membrane complex, Proteins encoded by the C, pneumonia e gene family seem to be dominant antigens in experimentally infected mice.