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Marked differences in CCR5 expression and activation levels in two South African populations
Author(s) -
Picton Anabela C. P.,
Shalekoff Sharon,
Paximadis Maria,
Tiemessen Caroline T.
Publication year - 2012
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/j.1365-2567.2012.03592.x
Subject(s) - cd16 , cd8 , biology , immunology , population , cell , natural killer cell , chemokine , chemokine receptor ccr5 , chemokine receptor , cytotoxic t cell , immune system , cd3 , genetics , medicine , environmental health , in vitro
Summary The chemokine receptor CCR5 is pivotal in determining an individual’s susceptibility to HIV‐1 infection and rate of disease progression. To establish whether population‐based differences exist in cell surface expression of CCR5 we evaluated the extent of CCR5 expression across all peripheral blood cell types in individuals from two populations, South African Africans (SAA) and South African Caucasians (SAC). Significant differences in CCR5 expression, both in number of CCR5 molecules per cell (density) and the percentage of CCR5‐expressing cells, were observed between the two study groups, within all cell subsets. Most notably, the percentage of all CCR5 + cell subsets was significantly lower in SAC compared with SAA individuals ( P < 0·01) among natural killer (NK) ‐cell subsets (CD56 + , CD16 + CD56 + and CD56 dim ) whereas CCR5 density was significantly higher in SAC compared with SAA individuals in CCR5 + CD8 + T‐cell subsets and CCR5 + NK‐cell subsets (CD56 + , CD16 + CD56 + and CD56 dim ) (all P < 0·05). These relationships were maintained after exclusion of CCR5Δ32 heterozygous individuals ( n = 7) from the SAC dataset. The SAA individuals exhibited significantly higher cell activation levels, as measured by HLA‐DR expression, than SAC individuals in CD4 + T‐cell subsets ( P = 0·002) and CD56 + NK‐cell subsets ( P < 0·001). This study serves to demonstrate that ethnically divergent populations show marked differences in both cell activation and CCR5 expression, which are likely to impact on both susceptibility to HIV‐1 infection and the rate of HIV‐1 disease progression.