Figure 8: Early treatment preserves HIV-specific CD4⁺ T cell responses.

HIV-specific CD4⁺ T cell responses were measured by IFN-γ ICS after overnight incubation in the presence of overlapping HIV-1 clade C peptide pools. (a) Representative flow plots gated on IFN-γ-secreting CD4⁺ T cells. (b) Aggregate data for frequencies of IFN-γ-producing CD4⁺ T cells in response to Gag, Nef, and Env peptide pools in 12 Fiebig I-II, 5 Fiebig II-III and 9 Un Tx are shown. Black dots denote a single measurement per donor, same coloured dots denote multiple measurements within a donor. Statistical significance was determined using multilevel mixed-effects linear regression analyses when comparing between groups to account for multiple measurements within some individuals. Horizontal lines represent median with interquartile range. (c) Flow cytometry of CFSE-labelled CD4⁺ T cells for 1 representative donor from each group measured at day 21 and day >250. (d) Aggregate CD4⁺ T cell proliferative responses measured between 14 and 42 days after diagnosis. (e) Aggregate CD4⁺ T cell proliferative responses measured after 120 days after diagnosis Data in panel d and e were generated 11 Fiebig I-II, 6 Fiebig III-V and 9 UnTx. (f) Aggregate CD8⁺ T cell proliferative responses measured between 14 and 42 days after diagnosis. (g) Aggregate CD8⁺ T cell proliferative responses measured 120 days after diagnosis. Data in panels f and g were generated from 11 Fiebig I-II, 5 Fiebig III-V and 7 UnTx persons. Statistical significance was determined using two tailed Mann-Whitney test. (h) Correlation between CD4⁺ and CD8⁺ T cell proliferative responses in 8 Fiebig I-II treated donors. Spearman’s rank correlation test was used. Two tailed p values are reported. (i) Representative flow plot depicting CD8⁺ T cell proliferation in unfractionated PBMC and in CD4-depleted PBMC. (j) Aggregate CD8⁺ T cell proliferative responses to HIV antigens with and without CD4⁺ T cells in 5 Tx Fiebig I-II donors. Statistical significance was determined using two tailed Mann-Whitney test. Horizontal lines represent median with interquartile range.