What does CCR5 protect against?

The CCR5-delta 32 mutation in a sense locks “the door” which prevents HIV from entering into the cell. 1% of people descended from Northern Europeans, particularly Swedes, are immune to HIV infection.

What is the CCR5 allele?

Homozygous carriers of CCR5-Δ32, a gene variant of CC-type chemokine receptor 5 (CCR5), are highly resistant to infections with human immunodeficiency virus type 1 (HIV-1) and therefore preferred stem cell donors for HIV-infected patients.

What is the significance of the CCR5 δ32 gene?

Recent research indicates that CCR5 Δ32 enhances cognition and memory. In 2016, researchers showed that removing the CCR5 gene from mice significantly improved their memory.

Is the CCR5 Δ 32 mutation associated with immune system related diseases?

It is likely that CCR5 plays a role in inflammatory responses to infection, though its exact role in normal immune function is unclear. The CCR5 delta 32 mutation is considered to be a risk factor for systemic autoimmune diseases as systemic lupus erythematosus, lupus nephritis, and multiple sclerosis [15, 16].

How old is the CCR5 Δ32 allele in humans?

The age of the Δ32 allele has been estimated to be between 700 and 3,500 y based on linkage disequilibrium data [ 2, 3 ], and recent ancient DNA evidence suggests the allele is at least 2,900 y old [ 4 ]. If Δ32 were neutral, population genetics theory predicts it would have to be much older given its frequency.

How are CCR5 Δ32 carriers resistant to HIV?

Homozygous carriers of the Δ32 mutation are resistant to HIV-1 infection because the mutation prevents functional expression of the CCR5 chemokine receptor normally used by HIV-1 to enter CD4+ T cells.

Where does the CCR5 Δ32 mutation come from?

To understand the origin and spread of Δ32, we modeled the effects of selection and dispersal on the allele. The Δ32 mutation is found only in European, West Asian, and North African populations.

Why did smallpox exerted positive selection for CCR5 Δ32?

The hypothesis that smallpox exerted positive selection for CCR5 Δ32 is also biologically plausible, since poxviruses, like HIV, enter white blood cells using chemokine receptors.