Shortened telomeres in the expanded CD28-CD8+ cell subset in HIV disease implicate replicative senescence in HIV...

Area of Science:

• Immunology
• Virology
• Gerontology

Background:

• CD8+ T cells are crucial for controlling HIV infection.
• An expanded population of CD28-CD8+ T cells with reduced proliferation is observed in late-stage HIV disease.
• This CD28-CD8+ T cell population resembles senescent cells found in aging individuals.

Purpose of the Study:

• To investigate if CD28-CD8+ T cells in HIV disease have shorter telomeres.
• To provide evidence for increased CD8+ T cell division in HIV infection.
• To explore the link between telomere shortening, replicative senescence, and T-cell exhaustion in HIV.

Main Methods:

• CD8+ T cells from HIV-infected and control subjects were isolated.
• Cells were sorted into CD28+ and CD28- populations using flow cytometry.
• Telomere length was measured using terminal restriction fragment (TRF) analysis via Southern hybridization.

Main Results:

• CD28-CD8+ T cells from HIV-infected individuals had significantly shorter telomeres (5-7 kb) compared to uninfected controls (P=0.003).
• The telomere length in these cells was comparable to that of centenarian peripheral blood mononuclear cells.
• This suggests the CD28-CD8+ T cells in HIV are in a state of replicative senescence.

Conclusions:

• Shortened telomeres in CD28-CD8+ T cells signify replicative senescence in HIV disease.
• This senescence offers a mechanism for impaired CD8+ T cell control of viral replication.
• Replicative senescence may contribute to T-cell exhaustion in chronic HIV infection.