Dendritic cells (DCs) transfected with a recombinant adenovirus carrying chlamydial major outer membrane protein antigen elicit protective immune responses against genital tract challenge infection.

Chlamydia trachomatis, an obligate intracellular bacterial pathogen, is the major cause of sexually transmitted diseases worldwide. Although a variety of strategies have been taken to promote the development of a protective vaccine, no ideal vaccine has been generated so far. In this study, we transfected dendritic cells (DCs) with recombinant adenovirus carrying C. trachomatis serovar E major outer membrane protein gene (Ad-MOMP), and investigated their ability to induce specific protection against genital tract chlamydial challenge infection. The results showed that when DCs were transfected with Ad-MOMP in vitro, the DCs exhibited increased expression of CD80 and MHC-II molecules as well as enhanced IL-12 secretion and were able to stimulate T-cell proliferation. The level of IFN-gamma secreted by stimulated T cells was also up-regulated significantly. When the Ad-MOMP transfected DCs were adoptively transferred intravenously to naive mice, they generated Th1-biased cytokine production and mucosal IgA responses specific for C. trachomatis. More importantly, the mice immunized with Ad-MOMP-DC mounted protection against genital tract challenge infection, shown by lower body mass loss, lower chlamydial loads, and less severe pathological changes. In conclusion, Ad-MOMP transfected DCs are capable of inducing effective protective immune responses against C. trachomatis genital infection.