A new study by a team of researchers at Stanford university, published in nature medicine, shows that experiments on rhesus monkeys show that a new vaccine significantly increases protection against HIV infection and continues to provide protection for up to a year after vaccination.
The researchers point out in their paper that current HIV vaccine development has focused on inducing neutralizing antibody (nAb) production, and that this new vaccine can produce neutralizing antibody while enhancing cellular immunity, thus enhancing the protection of the vaccine.
To test the effectiveness of the new vaccine, researchers vaccinated and tested 15 rhesus monkeys in three groups over a 40-week period.
The first group of rhesus monkeys received vaccines made of membrane proteins and adjuvants that stimulated antibody production and enhanced the immune response.The second group added three modified viruses that were not infectious but could stimulate cellular immunity.The third group was treated as a control group with only adjuvants.
Starting at 84 weeks after the first inoculation, the scientists exposed the rhesus monkeys to low doses of SHIV virus (simian HIV) for 10 weeks.Most of the animals in the control group were quickly infected, while the two experimental groups received significant protection, with 53.3 percent and 66.7 percent, respectively.
The researchers say the improvement is due to the vaccine stimulating the production of immune cells called tisses-resident memory T cells.These cells move to the site where the virus has entered, acting as sentinels, and if they see the virus again, they immediately start fighting it.
About 38 million people around the world are living with AIDS, causing about 770,000 deaths each year.”These results mean we are one step closer to the goal of using a vaccine to prevent AIDS,” said Rama Amara, a professor of immunology who was involved in the study.
The study also suggests that future vaccine development efforts should focus on elicitation of cellular responses and neutralizing antibodies, as well as on other pathogens, including influenza, tuberculosis, malaria and novel coronavirus.