Monday, March 16, 2009

HIV: The Wolf in Sheep’s Clothing

photo by sarahheiman

"I can’t live if living is without you”…these may be words sung and spoken by many, but if a virus could speak, these are the exact words it would say to the cell it infects. Viruses, such as HIV, act like parasites and use the proteins and replication machinery present in the host cells they infect in order to propagate themselves. When viruses replicate and bud out of the cells they infect (T cells in the case of HIV), they take along some of the cell’s proteins and incorporate them into their own viral envelope. Uninfected T cells also normally release small particles called microvesicles which are involved in modulating immune responses. When such microvesicles bud out of T cells, they take with them proteins from the T cell plasma membrane.

A recent study has examined the carbohydrate composition of proteins coating the surface of HIV derived from infected T cells to that of microvesicles derived from uninfected T cells. The study shows that the carbohydrates present on virions were the same as those found on native microvesicles, indicating that HIV can cleverly camouflage itself within the host by covering itself with a “coat” that closely mimics immunomodulatory microvesicles.

Reference: Krishnamoorthy L, Bess JW Jr, Preston AB, Nagashima K, Mahal LK. (2009) HIV-1 and microvesicles from T cells share a common glycome, arguing for a common origin. Nature Chemical Biology 5(4):244-50.

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