The ultimate aim of Sudaxshina Murdan's work is to develop vaccines that are taken orally by pregnant women in order to protect their babies from catching infections, such as HIV infection, from the mother's vaginal canal during birth.
In her pump-priming project "Oral vaccines which generate immune responses in the vagina and prevent mother-to-baby transmission of infections during birth," Murdan and her team tested whether targeting the vaccine to the large intestine (colon) would result in immunity in the vagina, which would then prevent microbe transmission from the mother to the baby. They conducted experiments in an animal model (female mice) using a model vaccine and delivered the vaccine to the animal's large intestine (via the anus) every week for 5 weeks. Subsequently, Murdan and her team measured the immunity in the vagina, the gut and the blood.
They found that delivering a vaccine to the colon gives rise to immunity in the vagina, as well as in the gut and blood. In contrast, injecting the model vaccine did not give any immunity in the vagina or in the gut. This shows the superiority of vaccination in the large intestine compared to injecting the vaccine when immunity in the vagina is desired.
The second part of the project was to investigate whether putting the vaccine in microparticles (very small carriers) would increase the immunity achieved. Murdan and her team produced several types of microparticles containing the vaccine and delivered them to the large intestine of mice. Contrary to expectations, putting vaccine in microparticles before delivering the vaccine did not increase the immunity. It is possible that the vaccine remained entrapped inside the microparticles, and therefore could not be processed by the body's immune system. The results showed that entrapping vaccine inside microparticles before delivering to the colon was not necessary.
Dr Chris Gale from Imperial College London provided new insights about the impact of COVID-19 on the health of neonates in a webinar organised by IMPRINT.