NIH Funded Scientists Find HIV-Blocking Protein in Monkeys
Discovery could shorten the path to an AIDS vaccine
A team of researcher supported by the NIH's National Institute of Allergy and Infectious Diseases (NIAID) identified a protein that blocks HIV replication in monkey cells. Humans have a similar protein, although it is not as effective at stopping HIV, say the researchers whose work is published in this week's issue of Nature.
"Identification of this HIV-blocking factor opens new avenues for intervening in the early stage of HIV infection, before the virus can gain a toehold," says NIAID Director Anthony S. Fauci, M.D. "The discovery also gives us critical insights about viral uncoating, a little understood step in the viral lifecycle. Basic discoveries like this provide the scientific springboard to future improvements in therapies for HIV disease."
The discovery could also shorten the path to an AIDS vaccine by making improved animal models of HIV disease possible. Because monkeys are not susceptible to the human version of AIDS, results of vaccine trials conducted on them are not directly applicable to humans. Now with a better understanding of why HIV cannot successfully infect monkey cells, scientists have a defined target to manipulate and could use that information to develop animal models that more closely mimic HIV disease.
Matthew Stremlau, Ph.D., a member of Dr. Sodroski's team and lead author on the new paper, searched the rhesus monkey genome and isolated a stretch of DNA that encodes the TRIM5-alpha protein. In a series of experiments using lab-grown cells that either possessed or lacked TRIM5-alpha, the scientists determined that TRIM5-alpha is both necessary and sufficient to block HIV replication. Although the precise mechanism of TRIM5-alpha's activity is not fully determined, says Dr. Sodroski, it may be that the protein chops up HIV's capsid and thwarts the orderly uncoating the virus must undergo before proceeding to replicate.
NIAID is a component of the National Institutes of Health (NIH), an agency of the U.S. Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on transplantation and immune-related illnesses, including autoimmune disorders, asthma and allergies.
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