期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2001
卷号：98
期号：24
页码：13984-13989
DOI：10.1073/pnas.241377698
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Chlamydia trachomatis is an obligate intracellular human bacterial pathogen that infects epithelial cells of the eye and genital tract. Infection can result in trachoma, the leading cause of preventable blindness worldwide, and sexually transmitted diseases. A common feature of infection is a chronic damaging inflammatory response for which the molecular pathogenesis is not understood. It has been proposed that chlamydiae have a cytotoxic activity that contributes to this pathology, but a toxin has not been identified. The C. trachomatis genome contains genes that encode proteins with significant homology to large clostridial cytotoxins. Here we show that C. trachomatis makes a replication-independent cytotoxic activity that produces morphological and cytoskeletal changes in epithelial cells that are indistinguishable from those mediated by clostridial toxin B. A mouse chlamydial strain that encodes a full-length cytotoxin caused pronounced cytotoxicity, as did a human strain that has a shorter ORF with homology to only the enzymatically active site of clostridial toxin B. Cytotoxin gene transcripts were detected in chlamydiae-infected cells, and a protein with the expected molecular mass was present in lysates of infected epithelial cells. The protein was present transiently in infected cells during the period of cytotoxicity. Together, these data provide compelling evidence for a chlamydial cytotoxin for epithelial cells and imply that the cytotoxin is present in the elementary body and delivered to host cells very early during infection. We hypothesize that the cytotoxin is a virulence factor that contributes to the pathogenesis of C. trachomatis diseases.
