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Discussion Starter · #1 ·
The two chemokines present on immune cells that serve as co receptors for the HIV entry into the cell.
Since these are relatively new discoveries and are the target of new novel therapies for HIV they have been frequently seen popping up in recent USMLE exams.
Here's a quick encounter that serves enough for the exam.

CCR5
Is a beta chemokine receptor present on human lymphocytes and macrophages and has been recently designated CD195 (unlikely to be seen in USMLE under this name).
It's believed that CCR5 is the cause for the HIV macrophage-tropism early in the infection.
The gene for CCR5 is located on chromosome 3 and delta 32 mutation results in absent production of this protein.
Persons who are homozygous for the mutation are believed to be almost totally resistant to HIV infections while those heterzygous for delta 32 mutation are believed to have partial resistance and HIV infection would be slow in these individuals.

CXCR4
Is the other alfa chemokine mainly present on T cells (T cell tropic) and typically used by the HIV virus late in the infection and it's unclear whether it is a cause or a consequence of HIV infection.
CXCR4 has been also named Fusin (don't confuse that with Fuzeon the trade name of Enfuvirtide which is new HIV fusion inhibitor that binds gp41 and blocks viral entry).
Some experimental drugs are targeting CXCR4 receptors as they also have a role in mobilizing hematopoeitic stem cells from the bone marrow to the peripheral circulation.

Here's a table summerizing the high yield differences
HIV coreceptors.JPG
 

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Ex-USMLE Forums Staff
Joined
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753 Posts
Discussion Starter · #3 ·
How can I print the table?
  1. Click on thread tools above
  2. Choose view printable version
  3. the table will change into a link
  4. click on that link
  5. then in the opened page right click on the table and choose save picture as
  6. save it to your computer
  7. then print it from there
 
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