By Andrea Hargraves 
Scientists have made several advances in designing a class of HIV vaccines that can provide broad protection against the virus, according to four new investigations that use different methods to obtain broad-spectrum neutralizing antibodies.
The results of these preliminary studies were published in journals Sciences, Science Translational Medicine that it Immunologythat it The four works describe new steps in the serial vaccination strategy, The Effie Agency reported on Thursday that an effective vaccine against the human immunodeficiency virus (HIV) has been found.
Experiments were conducted on rhesus monkeys and rats (mice). One of the proposals is in the first phase of clinical trials.
The authors include scientists from the US Scripps Research Institute, the University of Louisville, and the University of California, San Diego.
The HIV epidemic has entered its fifth decade, and the scientific community has devoted time and resources to developing vaccine candidates against the virus.
but, Health authorities still lack an effective and approved vaccine that stimulates broadly neutralizing antibodies. Able to neutralize the most common strains of HIV, The group was highlighted in an abstract in the journal Science.
One solution is a process called germ line selection, Researchers use a series of proteins directed by the immune system (immunogens) to direct and “prime” young B cells as they mature in places called germinal centers.
the goal It stimulates cells to produce broadly neutralizing antibodies against HIV.
José Alcamé, Director of the AIDS Immunology Unit at the Carlos III Health Institute, confirmed this The goal of any prophylactic vaccine is to stimulate the production of neutralizing antibodies by the immune system The antigen used must usually include or consist of the virus envelope or surface proteins.
These proteins interact with cell entry receptors, Therefore, blocking it with antibodies neutralizes the virus infection. Explanation of Spain's Science Media Center (SMC), a scientific resources platform.
The difficulty of obtaining the vaccine is due to the structure of the HIV envelopewhich makes it very difficult to achieve the neutralizing action of antibodies, detailed the virologist, who was not involved in the studies.
Given the difficulty of generating neutralizing antibodies against HIV, The authors of this new work instruct the immune system to generate a specific type of neutralizing antibody using a different immunogen.
At first it is simpler (so that it can be better identified) and then more complex and closer to the original envelope protein of HIV, explained Julia Blanco, head of the Virology and Cellular Immunology group at the AIDS Research Institute IrsiCaixa.
The HIV envelope protein contains different regions that are recognized by neutralizing antibodies. For a specific region (CD4 binding site), This strategy has already been used and has even reached human studies.
Now a second area appears (V3 loop rule) which can also be used in a similar way.
“If the two strategies are combined, a greater quantity and diversity of these neutralizing antibodies can be generated (making the potential vaccine more effective),” explained Blanco, who was not involved in the studies.
Serial vaccination can be an excellent strategy, But it may require an excessive number of immunogens, making it difficult to turn it into a product that reaches the populations most in need.
“There is a lot of work ahead of us,” SMC summed up.