Stephanie Dorosko and her colleagues at Dartmouth Medical School have succeeded in inducing MPR-specific antibodies in female goats. These antibodies are intended to prevent HIV-1 access and entry to the infant’s intestinal mucosa during breastfeeding. Their findings were published earlier this month in the journal Vaccine.
There is currently great interest in developing vaccines to protect infants born to HIV-infected women. This project aimed to develop a vaccine that induces HIV-specific antibodies in the colostrum, milk produced by the mammary glands in late pregnancy, preventing breast milk transmission of the virus. The researchers immunized two pregnant Alpine goats, while a third goat served as a control.
In the experimental group, goats were immunized with the MPR(649-684) peptide sequence, a potential vaccine that will hopefully induce HIV-specific antibodies to fight the virus. Immunizations were administered through three different routes: intramuscular, intranasal, and in the supramammary lymph node region. Samples collected after giving birth demonstrated the presence of MPR-specific antibodies in colostrum and milk. Therefore, peptide vaccines can effectively induce MPR antibodies in the colostrum of a lactating species.
Varying low levels of HIV-1 neutralization in CD4+TZM target cells were observed using immuno-precipitated antibodies.
In the study, only three pregnant goats were used for evaluation. The experimental result from this sample size is not statistically robust. Furthermore, since goats cannot be infected with HIV virus, the virus induction is only a proof-of-principle experiment.
Dorosko and her colleagues will continue work on the vaccine. To ensure the effectiveness and consistency of the vaccine’s neutralizing effect and to account for the genetic differences between ruminants and humans, the team will explore the same vaccine regimen with monkeys before considering humans. Future experimental attempts on monkeys will also allow them to test the induced antibodies more accurately.
After experimenting on non-human primates, a more exact effect of the induced antibodies will become apparent. In the future, there will hopefully be a well-defined protocol for immunogen specific antibodies, preventing the transmission of countless cases of HIV.