Local intravaginal vaccination of the female genital tract

Abstract

In a clinical trial the authors tested whether local intravaginal or oral vaccination would stimulate a mucosal immune response in the female genital tract. The whole cell/B subunit (CTB) oral cholera vaccine was used. Two groups of previously unimmunized volunteers were given three doses of vaccine at 2-week intervals: a first group of seven women received oral immunizations and a second group of seven women were immunized locally in the genital tract by mixing the vaccine with a well defined gel, eldexomer, and applying it directly in the fornix of the vagina. The women were given the first vaccination on day 10 of the menstrual cycle. Sampling of peripheral blood and of cervical mucus (CM) using an Aspiglaire syringe was performed immediately prior to the first dose and at 8-10 days following the last immunization. The study showed that while only three of the seven orally immunized women responded with detectable IgA and IgG anti-CTB antibodies in the genital tract, six out of the seven women in the locally vaccinated group responded with genital tract antibodies. The responses were also generally stronger and CM contained higher specific IgA and secretory component containing anti-CTB titres in the locally vaccinated group. Of the orally vaccinated individuals all responded with increases in serum anti-CTB IgG and 4,7 also exhibited specific IgA serum titres. By contrast, only 3/7 in the intravaginal group responded with increases in serum IgG and IgA anti-CTB titers following immunization. The authors conclude that local intravaginal vaccination using a well-defined gel appears to be the route of choice to stimulate immunity in the female genital tract.