Dr Anthony Fauci presented data at a plenary session at the HIV R4P conference on antibody targeting of the α4β7 integrin in a novel mechanism to control HIV infection. Antiretroviral therapy (ART) has been widely used to control HIV replication. Antiretroviral therapy (ART) may be effective in reducing death and morbidity in HIV infected individuals; but treatment is life-long and ART is not a cure.
α4β7 is an integrin that is used by T cells to home into the gut. HIV has been shown to bind to the α4β7 integrin,enhancing viral entry into cells. This phenomenon may explain why early on in HIV infection, the gut T cells are quickly infected and depleted.
Fauci described the study recently published in Science, where rhesus macaques were infected with SIV and then treated for 90 days with ART from 5 weeks post infections. An antibody, known as Vedolizumab, that targets the α4β7 was given to the macaques after 9 weeks post infection. These antibody infusions were repeated every 3 weeks up until week 32.
The results of the study showed that the antibody was able to control HIV replication after ART interruption for up to 2 years. The macaques had low to undetectable viral loads and their CD4 T cell counts were comparable to healthy controls. The mechanism is still not fully understood and more work is being done to address this.
The outstanding results of this study have initiated a small human clinical trial (15-25 people) to see if the results can be reproduced in humans. If so, this antibody may be used as a novel therapy for HIV treatment.
Presentation webcast: HIV Research for Prevention 2016 webcasts
Article by Thandeka Moyo