Plant source for HIV microbicide

US researchers have reported that transgenic tobacco plants can produce large quantities of griffithsin, a potent inhibitor of HIV entry into cells.

Griffithsin, derived from the red algae Griffithsia, is being studied as a potential element in vaginal microbicides, to prevent HIV from infecting mucosal surfaces.

However, the chemical has proven very difficult to synthesise. Now, researchers from the UK and the US, lead by Kenneth Palmer and Barry O’Keefe, have transduced Nicotiana benthamiana with a tobacco mosaic virus vector expressing the protein.

The plant-derived protein has been shown to have broad spectrum activity against HIV clades A, B and C, and also has been shown to no irritating and or inflammatory effects on cervical cells and in an animal model.

In a paper published in the Proceedings of the National Academy of Sciences, the researchers show they can manufacture enough griffithsin for use in a clinical trial.