Vibrio cholerae ghosts elicit the production of soluble immunostimulatory factors and prevent development of Chlamydia infection (INM3P.408)

Abstract

Abstract Infections by the obligate intracellular pathogen Chlamydia trachomatis cause infertility in women of childbearing age. Currently infections caused by the pathogen are treated with antimicrobial therapy. Bacterial ghosts offer a cost-effective, long-term, protective therapy as vaccine delivery vectors. In the present study we tested the hypothesis that factors contained in culture supernatant exhibit anti-chlamydial activity. THP-1 monocytes were differentiated into macrophages (Mdm) by incubating with phorbol myristate acetate (PMA). Activated Mdm were pulsed with Vibrio cholerae ghosts (VCG) for 24 h, followed by the addition of murine splenocytes for an additional 48 h. After 72 h the supernatant was collected and assayed for cytokine concentration. Samples presented observable levels of immunostimulatory factors necessary for containing or clearing infections with chlamydia. Following these assay results, Chlamydia pneumonia (MoPn) elementary bodies (EBs) were suspended in VCG-pulsed THP-1 Mdm supernatant (conditioned media) and used to culture HeLa cells. As a positive control, MoPn was suspended in Earle’s MEM - a medium used for HeLa cell culture. Immunostimulatory factors contained in the conditioned media prevented the development of Chlamydia infection forming units (5.87%) vs. our positive control (94.1%). These results indicate that immunostimulatory factors induced by VCG confer protective immunity against the development cycle of Chlamydia.