Cows are entering the field of HIV vaccine research. As described in a research report published in the journal Nature, Devin Sok, director of antibody discovery and development at the International AIDS Vaccine Initiative (IAVI), reported a strong HIV-blocking antibody within a few weeks - one that usually takes years The process that can be completed. At the moment when new energy is injected into HIV vaccine research, unexpected animal models provide clues to important issues.
One of the study's first authors, Sok, said: "One approach to preventive HIV vaccines involves trying to trigger a wide range of neutralizing antibodies in healthy people, but so far these experiments have not been successful in human and animal studies." This experiment shows that it is possible not only to produce these antibodies in animals, but also to do this reliably and quickly, and to use relatively simple immunization strategies in the right environment. ”
Scientists have known for some time that some people with chronic HIV infection produce a wide range of neutralizing antibodies (bnAb), which can overcome the high level of HIV diversity. A type of bnAb, first reported by IAVI, the Scripps Research Institute (TSRI) and Theraclone in 2009, used a long arm-shaped ring to reach hidden areas on the surface of the virus to stop infection. Experiments led by Vaughn Smider, a bovine antibody specialist at the Scripps Research Institute (TSRI), have shown that bovine antibodies also have ultra-long cycles that may be exposed to difficult epitopes that human antibodies cannot. This feature is related to HIV researchers because the virus has a sugar that is used to stop most antibodies from reaching their vulnerable sites.
Sok is a subsidiary of the IAVI Neutralizing Antibody Center (NAC), part of TSRI where several scientists work together to study antibody-based HIV vaccines. NAC was led by Dennis Burton, lead author of the study, TSRI Professor of Immunology and Microbiology. Like a bull in a science porcelain store, the Alliance of HIV, Antibody and Veterinary Scientists from IAVI, TSRI and Texas A&M University raises a colorful question: What happens if we immunize cattle with HIV immunogens ?
“This is a very simple and profound idea,” Sok said, working closely with TSRI's Dennis Burton. “Because we know that some human bnAbs have longer loops than the average length, will immunization of animals with similar antibody structures lead to bnAbs against HIV?”
The answer starts with a single protein on the surface of HIV as a target for bnAb - developing an antibody that recognizes variants of this protein on different HIV viruses and you may be protected from all of these viruses. One of the many techniques that HIV uses to stop humans from developing correct antibodies is to show an unrelated form of this protein to disperse the immune system. Scientists believe they have overcome this challenge by developing an immunogen called BG505 SOSIP, which mimics protein targets. Immunization with rhesus monkeys, guinea pigs, and rabbits with this immunogen is both encouraging and frustrating - so far, it has triggered very good antibodies against a strain of virus, but failed to lead to overcome HIV. Globally diverse antibodies.
All four cows immunized with BG505 SOSIP induced bnAbs to infect HIV within 35-52 days. In contrast, HIV-positive people take years to develop appropriate responses, and only 5-15% can even develop these responses.
Of course, cows cannot be infected with HIV. But these findings have set new targets for HIV vaccine researchers: By increasing the number of long-circulating human antibodies, we may be more likely to obtain protective bnAbs by vaccination.
There is no doubt that the ability of cows to produce bNAbs against complex pathogens (such as HIV) in a few weeks highlights a broader sense, especially for emerging pathogens.
IAVI CEO Mark Feinberg said: "Scientific innovations like this have driven this area ahead. "This surprising result deserves further exploration and has potential for HIV prevention and treatment, but also Rapid development of antibodies and vaccines against other infectious diseases. ”
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