Vaccine could leave a sweet taste in the mouth

11 June 2007

Vaccines save millions of lives each year, but because they're so expensive to produce and administer - usually through injections, which demands qualified people - they drain the pockets of developing countries.

Many believe, however, that hope will come in the form of cost-cutting oral vaccines. That's the pursuit that's occupied Nyasha Chin'ombe, who will graduate this week with a PhD in medical virology/microbiology, in his work on the South African AIDS Vaccine Initiative (SAAVI) programme with Professor Anna-Lise Williamson.

In a proof-of-concept study, Chin'ombe constructed a live but crippled Salmonella (typhoid bacterium) that could carry jellyfish and HIV and subunit vaccines to the immune system via the oral route. He then produced a recombinant Salmonella bacterium - featuring a new combination of genes - with high levels of the jellyfish and HIV vaccines.

When Chin'ombe fed the bacterium to mice, they developed the hoped-for immune responses against the jellyfish and HIV subunits.

"This research, therefore, suggested that Salmonella bacterium could be harnessed and used as a biological Trojan horse against diseases of interest," says Chin'ombe.

It's still early days, though. The approach shows much potential, but more work has to be done before the technology can be applied to humans.

Chin'ombe is currently a postdoctoral fellow in the Department of Clinical Laboratory Sciences at UCT, working on HIV DNA vaccines.

Chin'ombe would like to thank Dr William Bourn and Professors Enid Shephard and Williamson for their mentoring.

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