In the new study, published in Nature Communications , researchers from Karolinska Institutet show that the mucosa associated invariant T cells (MAIT cells) of the human immune system react to dynamic activity and reprogramming of gene expression during the initial stage of HIV infection.
The study fills a knowledge gap, as previously, the function of MAIT cells in this particular phase was not sufficiently clear. In recent years there has been substantial effort to understand how the immune system of people responds and acts in the first days and weeks of HIV infection.
“Thanks to close cooperation with the research Institute of the army Walter reed we have access to extensive Biobank, where we were able to examine the samples from individuals before and after HIV-infection, “says Professor Johan Sandberg, working in the Department of medicine at Karolinska Institute in Huddinge and senior author of the new study.
MAIT cells are part of the immune system. Their main task is to combat bacteria on the barriers of the body such as skin and mucous membranes. Among other things, MAIT cells play an important role in the fight against bacterial lung infections, such as tuberculosis. However, MAIT cells are also involved and in the time of HIV infection, although viral infection. This is probably due to the fact that the immune system of infected people is losing control over the bacteria when infected.
“Previous observations have shown that MAIT cells disappear at later stages of HIV infection. In this study, we see that MAIT cells are actually expanding at the initial stage, with strong activation to fight the bacteria, “says Johan Sandberg.
MAIT cells can help control the HIV virus in any degree, but when the infection becomes chronic, the number of MAIT cells in the body decreases. Unlike many other parts of the immune system, MAIT cells do not regenerate in the treatment of HIV infection.
“In the study, we also found that patterns of gene expression of MAIT cells is gradually changing at the initial stage, “says Johan Sandberg. “They acquire different characteristics and their antibacterial function is reduced, which may adversely affect the human immune defense“.
The study improves the understanding of what is happening at the initial stage of HIV infection. Earlier in this region lacked the knowledge.
“In ongoing studies in HIV have focused on the development of vaccines and drug discovery, “says Johan Sandberg. “The knowledge of how the immune system works in the initial phase of HIV infection, such as the activity and properties of MAIT cells may facilitate the search for future interventions“.