Gut microbiome may impact HIV vaccine immune responses


Preliminary evidence presented at the HIV Research for Prevention (R4P) Conference in Madrid, Spain suggests that the composition of the human gut microbiome may inform how well an experimental HIV vaccine can elicit an immune response. Vaccines reduce the risk of an infection by helping the human immune system to fight disease without exposing it to disease symptoms.  

In a late breaker abstract presentation titled: Human gut microbiota are associated with HIV-reactive immunoglobulin at baseline and following HIV vaccination, James Kublin M.D. of the HIV Vaccine Trials Network (HVTN) explained that the human microbiome and immune system shape each other through lifelong interactions. He and his team used 16S ribosomal RNA sequencing of stool samples to understand the role of the human gut microbiome in modulating the immune response to two experimental HIV vaccines.

The microbiota composition of study participants, from the HVTN 096 clinical trial, was analyzed at baseline and then at two weeks and at six months post vaccination. HVTN 096 was a phase 1 double blind placebo-controlled clinical trial to evaluate the safety and to compare the priming ability of NYVAC alone versus NYVAC + AIDSVAX® B/E, and DNA alone versus DNA + AIDSVAX® B/E when followed by NYVAC + AIDSVAX® B/E boosts in healthy, HIV-1-uninfected adult participants.

Detection of antibodies directed against the envelope (Env) glycoprotein 41 (gp41) were generally much higher than baseline responses to other HIV Env antigens, which is consistent with there being cross-reactivity between responses to gp41 and other immunogens, potentially from commensal organisms such as E. coli.  One microbial consortium that associated with high gp41 responses at baseline also associated with lower vaccine-induced gp120 responses at primary and durability timepoints (two weeks and six months post vaccination, respectively) and lower V1V2 responses at the durability timepoint. Conversely, a second consortium of microbes associated with low baseline gp41 responses and higher gp120 responses at primary and durability timepoints, including the V1V2 responses 6 months after the last vaccination.

“We have further evidence that the microbiome is likely impacting vaccine responses, and that these responses may play a role in whether people are protected from HIV or not”, said James Kublin Executive Director of the HVTN and principal staff scientist at the Vaccine and Infectious Disease Division at Fred Hutchinson Cancer Research Center.  

We are on a scientific journey to find a safe and effective HIV vaccine to prevent new HIV infections in the future
An estimated 35 million lives have been lost since the HIV/AIDS pandemic began more than three decades ago. The World Health Organization (WHO) estimated that 37.6 million people were living with HIV in 2016, and 1.8 million new infections were documented in the same year. There are an estimated 5,000 new HIV infections daily around the world. Key populations at risk of acquiring HIV, irrespective of epidemic type or local context, include men who have sex with men, people in prisons and other closed settings, sex workers and their clients, transgender people and people who inject drugs.

The HVTN, headquartered at the Fred Hutchinson Cancer Research Center, is the world’s largest collaboration facilitating the development of vaccines to prevent HIV/AIDS and has together with global partners demonstrated significant scientific progress in pursuit of a safe and effective HIV vaccine. Through an inclusive strategy, and by forging in-country relationships on four continents at 44 clinical trial sites, the network works collaboratively with global communities and partners in the search for an effective HIV vaccine. Primarily funded by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH), the network currently manages 18 active clinical trials of which four are large-scale in-human efficacy trials.


About Fred Hutchinson Cancer Research Center
At Fred Hutchinson Cancer Research Center, home to three Nobel laureates, interdisciplinary teams of world-renowned scientists seek new and innovative ways to prevent, diagnose and treat cancer, HIV/AIDS and other life-threatening diseases. Fred Hutch’s pioneering work in bone marrow transplantation led to the development of immunotherapy, which harnesses the power of the immune system to treat cancer. An independent, nonprofit research institute based in Seattle, Fred Hutch houses the nation’s first National Cancer Institute-funded cancer prevention research program, as well as the clinical coordinating center of the Women’s Health Initiative and the international headquarters of the HIV Vaccine Trials Network.


Aziel Gangerdine
HVTN: Director of Communications
C 206.384.0945 / O 206.667.7875