Scientists associated with the Cornell University Center for Advanced Technology (CAT) in Biotechnology have received a U.S. patent on an immune cell receptor protein that is believed to be the site of infection for the virus that causes AIDS.

Knowing in detail the nature of the receptor protein at the immune cell-virus fusion site should allow drug designers to block the chemical pathway that leads to AIDS, according to

Jay Chigurupati, vice president of Viral Therapeutics Inc.

The patent, "Peptide inhibitors of human immunodeficiency virus infection and virus-mediated cell killing block virus interaction with a novel cellular receptor," was issued Oct. 22 to Lee A. Henderson, president of the Ithaca-based company, and to two colleagues at Tulane Medical School, where Henderson taught when the so-called CS3 receptor protein was discovered in 1989 and reported in 1990.

CS3 receptor, as defined in the patent, may be the same receptor proteins whose identification was simultaneously announced last June by researchers at five laboratories, Henderson said. If the CS3 receptor is the crucial protein at the AIDS virus fusion site, Viral Therapeutics and the patent-holders will have a scientific and proprietary head start in the race to develop an HIV-blocking drug.

"This important discovery and the business development process that followed show how university-based resources can assist the innovative work of young biotechnology companies," said Lynn W. Jelinski, Cornell professor of engineering and director of the New York State Center for Advanced Technology in Biotechnology at Cornell. Established in 1995 and operating from laboratories at the Cornell Business and Technology Park, Viral Therapeutics regularly uses the DNA sequencing and synthesis facilities at the Cornell CAT. Chigurupati, a former technology-transfer specialist at the Cornell CAT, earned a Ph.D. in biology and an MBA at Cornell. Henderson is a member of the Cornell CAT's advisory board.

Blocking HIV at the cell receptor would be a potentially more successful alternative to current drugs that attempt to alter a continuously mutating virus, Henderson said, explaining the lock-and-key model for infection inhibition. A drug, functioning as an inhibitor compound, would have to reach the receptor "lock" and bind to it before peptide molecules of the virus "key" arrived. Bound to the receptor, the inhibitor drug would work like a broken key that seals a lock and prevents the use of other keys, he said.

The search for that inhibitor drug has already begun, as pharmaceutical companies scramble to screen hundreds of thousands of candidate compounds. Viral Therapeutics' role in the search is to develop drug-discovery assays. These assay systems are now under development by the company and will be used to screen for the drug, Henderson reported.

Their CS3 receptor assay, using recombinant proteins made by yeast, will join 12 other products that are sold worldwide by Viral Therapeutics, including drug-development "platforms" for hepatitis viruses, herpes viruses and cytomegaloviruses, according to Chigurupati.

"We're here in Ithaca," he said, "because of the ready access to specialized equipment at the biotechnology center, to the scientific expertise and to the business-strategy advice we need to make this company succeed."