An experimental vaccine can protect rhesus monkeys against a simian-HIV infection

16 October 2013

BPRC - 1. An experimental vaccine can protect rhesus monkeys against a simian-HIV infection

The development of a vaccine against HIV is complex, because the virus is constantly changing its composition.  After all, a vaccine must be effective against all strains. To circumvent this problem, a vaccine has been developed which is directed against parts of the virus that remain constant. In monkeys it was studied whether this vaccine could confer protection against the virus.

The Human Immunodeficiency Virus (HIV) contains variable elements that make it difficult for the immune system to generate an effective immune response. HIV also contains elements that need to remain constant because of functional restraints. A vaccine directed against these constant parts would therefore be effective against all virus variants. This has resulted in the development of an HIV vaccine consisting of a combination of these elements.

In order to test whether such a vaccine may provide protection against infection, a vaccine that is directed against the same conserved parts of the monkey HIV virus (the  Simian Immunodeficiency Virus (SIV)) was developed. Subsequently, monkeys were vaccinated with this vaccine and infected with SIV. At the same time, monkeys that had not received the vaccine, and monkeys that had received only a part of the experimental vaccine, were infected.

Two of the six vaccinated animals were protected against infection with a high dose of virus, whereas all 14 animals of the other groups were infected. The protected animals had the greatest amount of anti-SIV antibodies in their body. This could indicate that antibodies play an important role in the protection of the vaccine.

This study, published in the journal AIDS shows that a vaccine that is directed against constant regions of the virus can provide protection against infection with a high dose of virus.  This indicates that vaccine strategies that are directed against conserved parts of the virus may be successful.