Perhaps it’s not surprising that the venture capitalists on Sand Hill Road seemed a bit hesitant when Stanford University immunologist Dr. Peter Lee pitched his fledgling company’s business plan. After all, he was talking about making billions of genetically engineered bacteria that would colonize women’s vaginas to fight AIDS.

The genetic engineering part was understandable. But bacteria? Billions of them? Colonizing vaginas?

“We haven’t gotten a good reception,” said Lee, a co-founder of Santa Clara-based Osel. “It’s something completely novel.”

Yet a nationally known AIDS researcher, a high-ranking Merck executive and the National Institutes of Health believe there’s great promise in Lee’s idea. Indeed, they, along with a few private investors, are betting money on it.

“It’s a really innovative approach that’s worthy of more research,” said Roberta Black, topical microbicide team leader with the National Institutes of Health, which has given Lee and his collaborators $4.5 million in research grants.

Trillions of bacteria inhabit our bodies, most of them harmless or even beneficial. Think of it as your own ecosystem of microscopic fauna and flora — one that can make you quite ill if it shifts out of balance.

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