The search for a HIV vaccine has proven futile thus far, largely due to the fact that HIV is so mutable. HIV changes its surface so quickly that the antibodies made by the immune system cannot keep up with the ever-changing virus.

Simian immunodeficiency virus (SIV) is an animal model that is most similar to HIV. Dr. Phillip Johnson, professor at University of Pennsylvania, found a way to protect macaques from SIV using an antibody that neutralises the virus. The antibody’s mechanism is not known, nor has it been possible to make humans produce these antibodies.

However, other viruses can be used transport gene snippets into organisms. The adeno-associated virus (AAV) is used as a vector for treating haemophilia and congenital blindness by replacing missing genes. Johnson and his team used the AAV to inject artificially engineered SIV antibodies into the muscles of 9 macaques, where the muscle cells then started to produce the antibody and release it into the bloodstream. They were then injected with SIV and their health was monitored for 1 year.

Of the 9, only 3 showed any sign of SIV, and none of these developed AIDS. The other 6 monkeys showed no sign of SIV.

Dr. Johnson is confident that the same vector-mediated gene transfer can be applied to HIV and is hopeful to begin clinical trials soon. The final medication, while still a long way off, will contain several HIV antibodies so as to attack the virus in more than one way, with the intention of destroying mutant strains simultaneously.

-Maha Jegatheesan (42051123)

References:
Technology Review by MIT http://www.technologyreview.com/biomedicine/22663/page2/

Picture: http://www.csend.hu/magazin/0102/hiv2.jpg