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San Antonio Research Team Makes Potential Breakthrough In Preventing AIDS

Cristina Fernández Fimia

A San Antonio researcher who declared war on HIV decades ago finds a potential new defense against the virus.

Dr. Ruth Ruprecht discovered her mission in medicine more than 30 years ago, before AIDS had a name. And it would be years before researchers discovered the syndrome was caused by a retrovirus: HIV.

Credit Contributed Photo / Texas Biomedical Research Institute
Texas Biomedical Research Institute
Ruth Ruprecht

"When I was a young physician in training, I took care of young people my age,” she said. “They had unrecognizable conditions; no name was in the textbook for their condition. They all died. I was basically taking care of the very first AIDS patients."

Ruprecht added: "Once I discovered a retrovirus was the cause of it, I declared war on it.".

In the intervening decades, Ruprecht became a researcher. She is now the director of the Texas BiomedAIDS Research Program, and her team — led by Siqi Gong and Khamis Tomusange — may have discovered a new and potent defence against the virus in our own immune systems: immunoglobulin M.

Credit Texas Biomedical Research Institute
Texas Biomedical Research Institute
Immunoglobulin M is the first antibody to the body makes to fight new infection. It is now being enlisted in the fight against AIDS.

"IgM is kind of the forgotten immunoglobulin. It's the most ancient immunoglobulin. All vertebrate species have it. Even sharks make it. Birds have it. All fish have it,” Ruprecht said.

It was IgM's longevity the ultimately piqued Ruprecht's interest.

"I kind of said to myself, ‘If mother nature has bothered to keep this big molecule and using it, it must have an important function, and maybe it also can be recruited to defend against HIV transmission.’ And yes, it can,” Ruprecht said.

Until now, scientists had thought IgM was too short lived to have any real impact on HIV. They underestimated this antibody, Ruprecht said.

When enlisted into the HIV fight, IgM binds to the HIV particles, creating an even larger particle. The resulting molecule and virus are too large to pass through human mucous membranes, preventing infection.

Rupert said the discovery is significant because an estimated 90 percent of new infections worldwide are caused by exposure to the virus through mucous membranes.

This is also big for the scientist who declared war on HIV all those years ago.

"Yes, and we are not done yet," Ruprecht said.

Ruprecht’s study and and accompanying editorial were published in July in the Journal AIDS.

Bonnie Petrie can be reached at bonnie@tpr.org or on Twitter @kbonniepetrie