An article by researchers from Stanford University, Emory University, and the University of Minnesota (USA) is published in a journal. Nature medicine.
Despite more than three decades of intense research efforts by scientists to develop a prophylactic vaccine that protects against HIV infection, these efforts have so far been unsuccessful. In general, the task of vaccines is to elicit an adaptive immune response, which consists of two parts: humoral and cellular. When the humoral immune response in the blood plasma produces special molecules, antibodies that are able to capture and neutralize pathogens. With a cellular immune response, T cells of the immune system come into play, which move around the body, “inspecting” the tissue, and detecting cells infected with the virus, destroy them.
Most vaccines are based on stimulating a humoral immune response, that is, on an increase in the number of protective antibodies circulating in the blood. A new type of vaccine, unlike the previous ones, stimulates both types of immune response – and provokes the release of antibodies into the bloodstream, and makes the army of immune T cells work. As one of the authors, professor of microbiology and immunology at Stanford University, Bali Pulendran (Bali Pulendran) explained, in the case of HIV it is too difficult to achieve the desired level of antibodies in the blood and maintain it in the future. And stimulation of cellular immunity allows you to make protection against HIV more powerful, even with a relatively low level of neutralizing antibodies in the blood.
Pulendran and his colleagues tested the vaccine they created in 45 experimental rhesus monkeys. Animals were divided into three equal groups. One of the groups received a vaccine several times over 40 weeks containing the surface protein of the virus, which stimulates the production of antibodies, the second group received a vaccine that stimulates both types of immunity, and the third was a control. About a year later, macaques were infected with a virus similar to human HIV. As a result, it was found that a new type of vaccine provides animals with a much more powerful and long-lasting protection against virus infection than a vaccine based only on the production of antibodies. Moreover, the vaccine works even when the level of antibodies in the blood is relatively low.
“The results suggest that further efforts to develop vaccines not only against HIV, but also from other pathogens, including the new coronavirus, should be based on the stimulation of both humoral and cellular immunity,” Pulendran emphasized.
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