Go for the Green

A component of green tea called epigallocatechin gallate, or EGCG, blocks the ability of HIV to enter the immune system cells that it subverts and destroys as part of the AIDS process, according to researchers from Baylor College of Medicine and the University of Sheffield in the United Kingdom. Their report appears on the Web site of The Journal of Allergy and Clinical Immunology. The researchers generated a computer model of the structure of the EGCG molecule and were able to find the mechanism by which it prevents the HIV envelope protein gp120 from binding to CD4 cells. 'We found that the EGCG molecule itself binds to the same exact binding pocket on the CD4 molecule at the site of the same amino acids to which gp120 binds,' says Christina L. Nance, an instructor in pediatrics at Baylor. 'When it binds there'HIV can't.' The next step, Nance says, is to create a three-dimensional replica of the molecule for a definitive determination of EGCG binding and inhibition of HIV. From that, researchers may be able to model synthetic molecules that are even better at inhibiting HIV binding or additives that could make EGCG activity more sustainable. If EGCG proves to have value as an HIV treatment, Nance says, it probably will not be used alone, at least at first, but as part of a cocktail of medications.