Recently, Stanford University School of Medicine, Emory University and other institutions in the “Nature-Medicine” published the latest research results of the HIV vaccine. Researchers tested the protective effects of a new HIV vaccine, which was shown in macaques to produce a strong immune response that better protects against infection and provides lasting protection.
Source: China Science Daily
Author . . . Xin Yu
The researchers say the findings not only provide important insights into the prevention of AIDS, but also provide broad implications for the development of vaccines against other pathogens, including the recent pandemic of the new coronavirus.
“Arms” synergizes immunity
Sun Caijun, an expert in viral immunology and a professor at Sun Yat-sen University’s School of Public Health (Shenzhen), told the China Science Daily that the research and development process of HIV vaccine has gone through the stage of pure induction of body fluid immunity and simple induction of cellular immunity. The prevailing view is that an effective HIV vaccine should induce a balanced resonal immune response and a cellular immune response.
At present, the development of HIV vaccine mostly focuses on inducing neutralizing the production of antibodies, that is, allowing the immune system’s B cells to make more antibodies, so that the virus inactivation. The new vaccine designed by the team is to enhance cell immunity while producing neutralizing antibodies, that is, to promote a stronger antiviral response to T cells in the body, thereby enhancing the vaccine’s protective effect.
The researchers explain that if the production of neutralizing antibodies and cell immunity is likened to two “arms” in which the immune system works, then the “arm” of the cell immune response is strengthened, and even if the level of neutralizing antibodies is not so high, the synergy of the “arms” can achieve better protection.
To test the effectiveness of this “arms” vaccine, the researchers vaccinated and tested 45 macaques, divided them into three groups, and were given multiple injections over a 40-week period.
The first group of vaccines consists of membrane proteins, the former proteins on the outer surface of HIV particles, which stimulate antibody production, the latter often used to enhance the immune response, and the second group adds an additional three modified viral vectors that are not infectious but contain genes that encode viral protein Gag to activate cell immunity, and the third group, as a control, injects only azos. In week 80, the macaques received a boost in immunization.
Combined vaccines are efficient and durable
From the 84th week after the first vaccination, the researchers exposed the animals to the virus for 10 consecutive weeks with low doses of SHIV (monkey/human immunodeficiency chimeric.
It was found that most of the macaques in the control group were quickly infected with the virus, while the other two groups were significantly protected. Of these, 53% of the macaques in the first group were uninfected, and 67% of the macaques in the second group were uninfected. This suggests that the combination vaccine gives the second group of macaques more protective.
It is worth mentioning that the first group of macaques in high titration of neutralizing antibodies is the key to prevent infection, while in the second group, some macaques in the body of neutralizing antibody titer is not high, did not meet the previously thought threshold, but the macaques were more protected.
“In the past, it has been thought that only increased neutralizing the efficacy of antibodies is the key to making vaccines more effective, and it has been very difficult to do so. Cynthia A. Derdeyn, one of the authors of the paper and a professor at Emory University, said that from the current results, the “arms-” synergy that researchers expect to have in the absence of neutralizing antibodies has had an effect.
Nearly a year after the macaques were vaccinated, the researchers again infected the macaques with more SHIV. The results showed that after repeated exposure to the virus, the second group of combined vaccines kept two-thirds of the macaques from being infected. The protective effect of the combined vaccine was more durable than in the first group.
The researchers analyzed that the new vaccination program improved the effectiveness, possibly because of the vaccine-induced production of CD8-T cells. These cells move to the site of the virus’s invasion and stay for a period of time to act as a “sentry”. If the virus is seen again, these cells act immediately, secreting signals to other nearby immune cells to fight the virus at the site of infection.
Or enlightenment to the development of new crown vaccines
“Researchers are experimenting with HIV vaccine design in a variety of ways, including using different antigen designs, delivery vectors, adjusites, and immune pathways, and these experiences are gradually expanding to other vaccine areas, such as influenza and TB. Sun Caijun said.
Rama R. Amara, one of the authors of the paper and a professor at Emory University, said the HIV vaccine was designed to be similarly feasible in vaccine development for other pathogens, including influenza, tuberculosis, malaria and now the new coronavirus.
An unnamed expert on viral vaccine development told The Chinese Journal of Science that neutralizing antibodies and T-cell immune responses play an important role in controlling new coronavirus infections. However, the infection immunology mechanism of the new coronavirus has not been fully explained, and its immune protection mechanism is still to be studied.
The experts believe that although traditional vaccines are to induce neutralizing antibodies as the main purpose, but in view of the new coronavirus some antigen epitope antibodies may have enhanced infection effect (ADE phenomenon), currently researchers in the design of induced antibody-based new coronary vaccine, need to consider safety factors.
“If we can induce a balanced body fluid immune response and T-cell immune response, it is possible to avoid this ADE phenomenon and play a good protective effect.” He said.