Adhesion Vaccine Candidate for Chlamydia Trachomatis

Chlamydia traehomatis is a major cause of sexually transmitted disease and blindness.Development of an anti-chlamydial subunit vaccine appears feasible. Nearly all subunit vaccine studieshave used the major outer membrane protein (MOMP) as the immunogen with only modest success.The identification of alternate surface proteins to test as vaccine candidates could significantly hastenthe development of an effective vaccine. MicroCarb has developed a novel approach for identifying keysurface adhesion proteins using various cell surface receptors. This approach was used with chlamydiato demonstrate specific binding of chlamydia to a distinctive cell membrane receptor component. Usingthis component as an affinity binding substrate, a novel membrane-associated protein, distinct frompreviously characterized chlamydial proteins, has been identified which binds this receptor. Theproposed research will characterize this novel membrane protein with antisera generated againstchlamydial membrane surface proteins of similar size. The antisera will be used to facilitate cloning ofthe gene encoding the receptor binding protein from a Chlamydia traehomatis gene bank generated inan E. coli expression system. Immunoreactive clones will be evaluated for expression of the novelreceptor- binding protein and for their ability to absorb antibody that inhibits receptor binding and/orinfectivity by C. traehomatis in vitro. Identification of a novel adhesion will permit evaluation of thisprotein as a subunit vaccine in a preclinical phase II application.