Education

Face of a killer

Toy de Lange points to the model he built of the HIV virus. Toy is a PHd student at the MRC's centre for Molecular and Cellular Biology and was recently commissioned to build this model for educational purposes.

The idea behind the model is to actually show people what the virus looks like and using the model to explain how the virus affects the immune system. Giving people something to look at makes this killer easier to understand. The model has been used in several exhibitions as an aid to answering questions people may have. Photos of this model have even been used in a presentation to President Thabo Mbeki's controversial Aids Advisory Panel, "to try and convince some of the dissidents who claimed that HIV has never been isolated, that HIV does exist and that there is overhwelming evidence that this virus causes Aids".

 Using the model, questions such as "how exactly does AZT work", are easier to explain: "The virus binds to a CD4-positive T-lymphocyte - one of your immune cells.  The virus then fuses with the lymphocyte, and its genetic material, which is RNA, enters this cell and undergoes reverse transcription into DNA - a necessary step for the reproduction of the virus. Reverse transcriptase - an enzyme in HIV - is necessary to catalyse this conversion of viral RNA into DNA. And, it is at this level that antiretroviral drugs such as AZT exrtes its effect, by inhibiting reverse transcriptase."

For the full article and more information please contact Izelle Theunissen, MRC News, izelle.theunissen@mrc.ac.za

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