Localization of the hypothetical protein Cpn0797 in the cytoplasm of Chlamydia pneumoniae-infected host cells.

Using antibodies raised with chlamydial fusion proteins, we have localized a protein encoded by the hypothetical open reading frame Cpn0797 in the cytoplasm of Chlamydia pneumoniae-infected host cells. The anti-Cpn0797 antibodies specifically recognized Cpn0797 protein without cross-reacting with either CPAFcp or Cpn0796, the only two proteins known to be secreted into the host cell cytosol by C. pneumoniae organisms. Thus, Cpn0797 represents the third C. pneumoniae protein secreted into the host cell cytosol experimentally identified so far.