Understanding HIV:
CCR5 and fusin—co-receptors for HIV
January 2003 View PDF En
español
Two new proteins found on immune cells, CCR5 and fusin (also known
as CXCR4), play a key role in understanding how HIV infects cells.
Though these discoveries may not have immediate impact on people
with HIV, they may lead to important advances in HIV treatment,
prevention and research in the future.
One way HIV disables the immune system is by infecting and destroying
CD4+ T-cells. These cells are critical in managing immune responses
and when they are depleted, immune defenses are weakened. When HIV
and other pathogens enter the body, CD4+ cells, operating through
a network of chemical interactions, instruct other cells to disable
the invading organisms. HIV actually attaches to the CD4+ protein
on the surface of these and other cells to gain entry.
CD4+ can be likened to a doorway that HIV uses to enter the inner
compartments of the cell. However, experiments in test tubes suggest
that the CD4+ protein alone is not enough to allow viral entry into
cells. Scientists believe they have now identified a second doorway
that the virus needs to open to infect a cell, and they have learned
that this receptor may be different for different types of cells.
One is called CC-CCR5 (CCR5 for short), and another is called CXCR4
or fusin.
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