FIG. 9.

Relationship between viral load and SIV-specific cellular immunity in naturally SIV-infected sooty mangabeys. (A) SIV-specific IFN-γ ELISPOT responses in 25 mangabeys assayed over a total of 85 time points. The P values for these correlations were determined by mixed-effects linear regression for repeated measurements. (B) Correlation between the breadth of SIV-specific ELISPOT responses and viral load in 25 sooty mangabeys. ρ and P were determined by the Spearman rank correlation test. (C) Correlation between viral load and frequency of SIV-specific CD8⁺ T lymphocytes in 13 naturally SIV-infected sooty mangabeys, as determined by the Spearman rank correlation test. Sums of positive CD8⁺ T-cell responses to different SIV proteins are shown. (D) Box plot comparing the frequencies of SIV-specific CD8⁺ T lymphocytes in six sooty mangabeys with low-level viremia (<10⁵ SIV RNA copies/ml) to those in seven mangabeys with high-level viremia (>10⁵ SIV RNA copies/ml). P was determined by the Mann-Whitney U test.