Inhibition of Chlamydia trachomatis replication in HEp-2 cells by human monocyte-derived macrophages.
Monocytes (M) and macrophages are important components of the immune response to foreign agents. Using an in vitro system, we studied the influence of human M and M-derived macrophages (MdM) on the replication of Chlamydia trachomatis (L2/434) in HEp-2 cells. M or MdM were added to infected cells at a ratio of 4:1, and the resultant chlamydial yield was evaluated in one-step growth experiments. Chlamydial DNA production was evaluated by dot hybridization. Both M and MdM reduced chlamydial yield and DNA production, but the reductions caused by MdM were more pronounced. Electron microscopy showed that while control HEp-2 cells at 48 h postinfection contained large inclusions in which most particles were elementary bodies, the infected HEp-2 cells exposed to MdM contained small vacuoles with abnormal reticulate bodies and very few typical elementary bodies. Separation of the MdM from the HEp-2 cells by a membrane reduced the inhibitory effect of the MdM relative to that of MdM in direct contact with the infected cells. Addition of tumor necrosis factor antibodies to C. trachomatis-infected HEp-2 cells exposed to MdM (either in direct contact or separated by a membrane from the infected cells) reduced the inhibition of chlamydial DNA production. These data suggest the possibility that MdM may modulate C. trachomatis replication in vivo.
Manor
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Virology Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Sarov
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D002460:Cell Line; D002692:Chlamydia trachomatis / Q000254:growth & development / Q000276:immunology*; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000276:immunology*; D008854:Microscopy, Electron; D009000:Monocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
D004269:DNA, Bacterial; D014409:Tumor Necrosis Factor-alpha