Marked differences in CCR5 expression and activation levels in two South African populations
Article first published online: 2 JUL 2012
© 2012 The Authors. Immunology © 2012 Blackwell Publishing Ltd
Volume 136, Issue 4, pages 397–407, August 2012
How to Cite
Picton, A. C. P., Shalekoff, S., Paximadis, M. and Tiemessen, C. T. (2012), Marked differences in CCR5 expression and activation levels in two South African populations. Immunology, 136: 397–407. doi: 10.1111/j.1365-2567.2012.03592.x
- Issue published online: 2 JUL 2012
- Article first published online: 2 JUL 2012
- Accepted manuscript online: 17 APR 2012 12:33PM EST
- Received 7 February 2012; revised 3 April 2012; accepted 11 April 2012.
- South African populations
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 CD56dim) 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 CD56dim) (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.