The Virus Within Can Change!

An article in the March issue of Nature Medicine indicates that the acquired immunodeficiency syndrome (AIDS) virus changes while in the body to become more destructive. This study confirms what other researchers thought was true.

People have seen the AIDS virus change in humans over the years of an infection. Initially the AIDS viruses preferred to invade and destroy macrophages (scavenger cells that live in the body's tissues) and other immune cells called T-helper lymphocytes. These viruses are called an M-tropic virus because they like to invade macrophages. After infecting the human body the viruses start to change due to changes in their DNA. Eventually more destructive forms of the virus results that are called T-tropic viruses. They are called T-tropic viruses because they invade T helper lymphocytes and rarely infect other types of cells. Eventually, the T-tropic viruses destroy the person's immune system and that is when people start getting ill with AIDS.

The exciting part of this research is that an in vitro model (a model that does not occur in animals or humans) was developed to determine why the AIDS virus is more destructive the longer it infects a person. These researchers (Svetlana Glushakova, Jean-Charles Grivel, Wendy Fitzgerald, Andrew Sylvester, Joshua Zimmerberg, and Leonid Margolis) used pieces of tonsils that had been removed from patients to grow the AIDS virus in tonsil cells on special sponges.

Dr. Margolis and his coworkers showed that, when T-tropic viruses infect the pieces of tonsil, the cells in the tonsil are not able to respond to the infection. However, when M-tropic viruses are used to infect the pieces of tonsil, the tonsil cells actually make a lot of antibody. Antibodies are useful in slowing down or eliminating organisms infecting our bodies. This study provides further proof to the idea that changes in the AIDS virus types can result in a more deadly virus population. It also confirms the findings that T-tropic viruses are much more destructive and that is because they can suppress the bodies immune response to the AIDS virus.

Hopefully this model for studying the AIDS virus will be useful in developing successful vaccination strategies and in better understanding how the AIDS virus causes damage to humans.

Take Care and Think Microbiologically!

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