a bit of history

[Guest guest]

I had heard it is more common for people in northern Europe to be immune from

aids. here is the explanation why: I am very familiar with ccr4 and ccr5 cell

receptors because there is an anti-HIV medication called Maraviroc (Selzentry)

that only works on ccr5-tropic HIV virus.

It turns out that some strains of HIV use the ccr4 receptor to gain

entry into white blood cells and other strains of HIV use the ccr5 receptor to

gain entry.

Maraviroc is a ccr5 receptor antagonist -- it blocks the ccr5 receptor. So

any HIV particle that looks to gain entry into a cell by the ccr5 receptor

attachment, will be blocked by the medication maraviroc. It's called an " entry

inhibitor " .

So, before a patient is started on maraviroc, they have what's called a

tropism test. It checks to see if the HIV virus in their bodies is ccr4-tropic

(uses the ccr4 receptor to gain entry into cells) or ccr5-tropic (uses the ccr5

receptor to gain entry into cells.) If the HIV in a particular patient's body

is ccr5 tropic, you can expect maraviroc to help that patient control their HIV

infection. On the other hand, if the HIV in a patients body is ccr4 tropic,

then Maraviroc will not help them at all.

I had forgotten that the mutated ccr5 receptor was selected for by the Black

Plague in Europe (the Yersenia pestis bacterium). Those who had the ccr5

receptor were protected from Yersenia pestis and therefore immune for the black

plague. Since those with the mutated receptor survived (and went on the have

children, passing their genes for the mutated ccr5 receptor into the next

generation) while those without it perished from the plague (therefore had no

offspring in whom to pass their ccr4 receptor genes) the ccr5 mutation became

more common in the European population over time. Fascinating!

amazing the same mechanism that protected one from the plague also protects one

from aids.