Figure 3.

HIV causes CD4 T cell death by inducing DNA damage and disrupting telomeres via inhibition of telomerase during early viral infection. (A) Representative dot plots and gating strategy of γH2AX levels in p24⁺ and p24^- CD4 T cells with HIV infection at day 7. Isotype staining and uninfected CD4 T cells serve as negative controls for flow cytometry. (B, C) Summary data of γH2AX % in HIV-infected (p24⁺ vs. p24^-) and uninfected cells at days 3, 5, and 7. (D) Western blot analysis of γH2AX levels in HIV-infected versus uninfected CD4 T cells at day 5. (E–G) Representative overlaid histograms and summary data of the mean fluorescence intensity (MFI) of telomere length in HIV-infected (p24⁺ or p24^-) and uninfected CD4 T cells at days 3, 5, and 7, as determined by Flow-FISH. (H) Representative imaging and summary data of meta-FISH analysis of the frequencies (%) of chromatin with fragile telomeres and telomere-free ends in CD4 T cells with or without HIV infection at day 5, measured by confocal microscopy. (I) Telomere length in CD4 T cells with or without HIV infection at day 5. Telomeric DNA was treated with or without FPG and analyzed by Southern blot. (J, K, O) Representative dot plots and summary data of the human telomerase (hTERT) % in HIV-infected (p24⁺ or p24^-) and uninfected CD4 T cells at days 3, 5, and 7. (L) Western blot analysis of hTERT levels in HIV-infected versus uninfected CD4 T cells at day 5. (M) Correlation analysis between hTERT expression and telomere length. (N) Correlation analysis between hTERT expression and γH2AX level in HIV-infected and uninfected cells.