Promising SIV Vaccine Increases Hope for HIV Vaccine

A scientific journal, Nature, recently reported that researchers have discovered a vaccine for the Simian Immunodeficiency Virus (SIV). This virus is very similar to the Human Immunodeficiency Virus (HIV).

Researchers in this study gave 24 Rhesus monkeys a genetically modified vaccine called Rhesus cytomegalovirus (Rhesus-CMV). Out of all the monkeys, 13 proved to be protected against SIV, and 12 were still protected after a year.

Scientists believe that HIV originated in primates, which makes this newly discovered SIV vaccine especially significant toward developing a vaccine for HIV. 

Vaccines contain a weakened or killed portion of bacteria, toxins or viruses. The harmless agent in the vaccine will stimulate an immune reaction in the individual. The immune system will see the agent as foreign, destroy it, and then remember it. This “memory” will allow the immune response to be stronger and faster upon an encounter with the harmful, whole pathogen, preventing infection. Some important vaccines include chicken pox, small pox and polio.

Researchers found that the SIV vaccine worked by increasing the number of effector T cells or helper T cells specific to the virus in the Rhesus monkeys. Helper T cells are important because they “help” to direct cells of the immune system, like macrophages and B-cells, which are important for fighting infection. Similar to SIV in monkeys, in humans, HIV kills these cells, leaving the affected individual vulnerable to opportunistic infections. 

While this study is promising, researchers must assess how safe introducing a vaccine composed of CMV into humans will be. Many of us have already been exposed to this virus, and some believe it to be harmless. However, CMV can cause a number of complications in humans. It is important that scientists ensure that using CMV as a vector would be just as safe in humans as it was in the Rhesus monkeys.

Source: Nature, International Weekly Journal of Science
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