They show that the combination of vaccines improves immunity against HIV

a team of CSIC National Biotechnology Center (CNB-CSIC), together with an international consortium, showed that vaccine combination and the period of administration are decisive for obtaining early and memory immune responses against the HIV virus. The results of the study were published in the journal Frontiers in Immunology.

This study in rhesus monkeys demonstrates the importance of vaccine combination and administration times to obtain better immune responses against HIV

Mariano Esteban, CNB-CSIC

“This study in rhesus monkeys demonstrates the importance of combining vaccines and timing of administration to obtain better immune responses against HIV”, explains the virologist Mariano Esteban, co-author of the work. “This result is applicable to other vaccines,” he adds.

To control HIV infection, a powerful immune response sustained over time is required, with the generation of broad-spectrum neutralizing antibodies, and the activation of memory B and T lymphocytes (white blood cells) specific against the virus.

International efforts to contain AIDS

Due to the importance of this infection and the disease it causes, AIDS, it is essential to develop an effective vaccine against this pathogen, which causes 700,000 annual deaths on a planetary scale.

“In this international project, we characterized the effect of the combination of three types of vaccines in monkeys: one based on nucleic acid (DNA), another on a non-replicating poxvirus vector in human cells (NYVAC) and a third on the Env protein of the envelope of the HIV together with an adjuvant”, lists Esteban.

The main questions raised by the researchers were, on the one hand, whether co-administration of the Env protein along with the DNA vaccine or NYVAC can accelerate the antibody induction and, on the other hand, if it is possible to improve the quality of immune responses correlated with protection by the addition of late booster doses.

Different vaccines and administration times

Different combinations of DNA, the NYVAC vector and the Env protein were administered intramuscularly to Rhesus monkeys divided into groups of 8 to 12 animals. These primates were inoculated at 0, 4, 12 and 24 weeks and the effect of re-immunization at 36 and 48 weeks was studied to see if it improved their immune response.

Beatriz Perdiguero, first author of the research, indicates that “the different regimens induced broad, polyfunctional and balanced immune responses in terms of activation of CD4 and CD8 T lymphocytes. Likewise, there was also a high production in plasma of antibodies that bind to the V1/V2 domains of the Env protein and another, more modest, of cytotoxic cell-dependent antibodies (ADCC) and neutralizing antibodies”.

Those bookmarks Immune systems are considered essential to achieve control of HIV infection. The authors conclude that the use of the Env protein as the first vaccination dose administered together with DNA or the NYVAC vector represents a optimized immunization protocol against HIV.

These studies are important in the development of HIV vaccination strategies, enhancing the different components of the immune system that can control the resistance of the virus to the action of vaccines.

Mariano Esteban, CNB-CSIC

“These studies are important in the development of vaccination strategies against HIV, as they potentiate the different components of the immune system that can control the resistance of the virus to the action of vaccines”, emphasizes Esteban.

In addition, the researcher adds, “they provide information on how continuous administration of vaccines does not exponentially increase the induced immune response beyond the fourth dose, which may be applicable to the effect that increasing the booster dose may have against the coronavirus” .