By Sebastian Dobosz
Researchers at St. Joseph’s Healthcare Hamilton have taken the first steps towards a widely protective vaccine against chlamydia.
Chlamydia is one of the most common sexually transmitted infections and affects 113 million people around the world. The disease causes pelvic pain in women, leads to other infections, and can cause irreversible damage resulting in infertility. As many chlamydia infections are asymptomatic, they can go untreated and cause damage without the patient being aware of the infection.
While chlamydia is currently treated with antibiotics, a vaccine would prevent the infection from occurring in the first place. This could potentially protect millions of people from chlamydia.
The researchers successfully tested a new recombinant antigen called BD584 in animal models with a common strain of chlamydia. The vaccine was delivered into the nose and protected the mice from genital tract infection as well as its damaging symptoms.
“The BD584 vaccine candidate is a fusion protein consisting of three genetically engineered proteins fused together,” says Dr. James Mahony, virologist at St. Joseph’s Healthcare Hamilton and the study’s senior author. “The vaccine elicits the production of antibodies that can block an essential virulence factor of chlamydia required for infection of cells therefore rendering the bacteria incapable of infection.”
The study showed that BD584 reduces chlamydial replication and shedding in the lower genital tract by 95 per cent, which is what enables the bacteria to spread to the upper genital tract. The vaccine also decreased pathology of the fallopian tubes by 87.5%. Dr. Mahony explained that chlamydial infection of the upper genital tract leads to fluid filled fallopian tubes that block fertilization of eggs.
“The advantage of our vaccine is that it provides protection against all strains of Chlamydia that infect the genital tract. It is the first vaccine to provide this wide scale coverage,” says Dr. Mahony. “It will also protect against those strains of Chlamydia trachomatis that cause conjunctivitis in the eye leading to scarring trachoma and blindness which affects between six to nine million people around the world.”
Dr. Mahony notes that future research on other animal models will need to be done before the vaccine is tested in human trials. Further research will also test the effectiveness of this vaccine against different strains of chlamydia.
Sebastian Dobosz is a Research Communications Officer at St. Joseph’s Healthcare Hamilton.