Relationship of Total CD8+ T Cell Activation to T Cell Maturation Profiles.

<p>Relationship between total CD8+ T cell activation levels at visit 1 (pre-treatment) on the x-axis and the maturation profile of CD8+ and CD4+ T cell populations, total or antigen specific. In the first panel total CD8+ T cell activation is higher when a greater fraction of total CD8+ T cells fall in the intermediate memory (CD27+CD28−) phenotype. In the second panel total CD8+ T cell activation levels are higher when a greater fraction of HIV-1 Gag specific CD8+ T cells fall in the intermediate memory (CD27+CD28−) phenotype. In the third panel total CD8+ T cell activation levels are lowest when a lower fraction of HIV-1 Specific CD4+ T cells fall into the early memory (CD27+CD28+) phenotype.</p

Magnitude of CD4+ and CD8+ T Cell Responses to HIV-1 Gag and CMV pp65. at each of the three study visits.

<p>Proportion of IFN-γ+ and IFN-γ+IL-2+ CD8+ (columns 1 and 2) and CD4+ (columns 3 and 4) T cells, responding to stimulation with Gag and pp65 peptide pools. Results for visit 1, prior to antiretroviral therapy visit 2, during a virologically suppressive anti-retroviral regimen, and visit 3, after patients had halted an anti-retroviral regimen and viremia had rebounded are shown in upper, middle and lower rows respectively. Black bars indicate differences between HIV-1 Gag and CMV pp65 responses by response category (Wilcoxon 2 Sample Test). Red dot (1^st column, 2^nd row) notes a significant change from baseline (visit 1) values (Sign Rank Test). Only the CD8+ T cell IFN-γ response to Gag was observed to significantly change (in this case decline) from visit 1 to either visit 2 or visit 3.</p

Activation levels on total and antigen specific T cells by differentiation stage.

<p>In the first column the proportion of total T cells (CD8+ and CD4+) expressing CD38 and HLA-DR activation markers by T cell maturation category are displayed and defined as early memory (CD27+CD28+) EM, intermediate memory (CD27+CD28−) IM, and late memory (CD27−CD28−) LM. In columns 2 the CD38 MFI level is shown by maturation stage for CD8+ T cell IFN-γ responses to both HIV-1 Gag (red) and CMV pp65 (green). And in column 3 the CD38 MFI is shown for each maturation stage of CD4+ T cell IFN-γ responses to HIV-1 Gag (red) and CMV pp65 (green). Row 1 displays measurements for visit 1, prior to antiretroviral therapy. Row 2 displays measurements for visit 2, during a virologically suppressive anti-retroviral regimen, and row 3 displays measurements for visit 3, after patients had halted an anti-retroviral regimen and viremia had rebounded. Black bars indicate differences between activation levels by response categories (Wilcoxon 2 Sample Test). Red dots notes a significant change from baseline (visit 1) values (Sign Rank Test).</p

T cell activation declines during anti-retroviral therapy but maturation profile of Gag specific CD8+ T cells does not change

<p>HIV-1 RNA levels, total CD8+ T cell activation levels, HIV-1 specific CD8+ T cell activation levels and the proportion of HIV-1 Gag specific IM and LM CD8+ T cells at visit 1 (Pre-ART), visit 2 (On ART) and visit 3 (Post-ART). P-values for changes in viral load, Total and HIV-1 specific CD8+ T cell activation are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004408#pone-0004408-t001" target="_blank">Table 1</a>. HIV-1 RNA, total CD8+ T cell activation levels and HIV-1 gag specific CD8+ T cell activation levels all declined after initiation of ART. Black bars display p-values for a test of change in HIV-1 Gag specific CD8+ T cell IM and LM fractions from visit 1 to visit 2, and visit 3. Neither the Gag specific IFN-γ+ CD8+ IM or LM pool changed significantly from pre-therapy levels after therapy was initiated (On ART), or later halted (Post-ART).</p

A More Differentiated Gag Specific CD8+ T Cell Response is Protective in Early HIV-1 Infection.

<p>Spearman Correlation results shown. Correlation performed on data from pre-treatment, Visit 1. Patients with higher CD4+ T cell counts during early infection and prior to anti-retroviral therapy tended to have higher HIV-1 Gag specific IFN-γ late memory (CD27−CD28−) CD8+ T cells</p

Expression of Maturation and Activation markers on Total CD4+ and CD8+ T cells.

<p>(A): before initiation of ART (i); after treatment (ii); and post-ART (iii). Activation is also shown on CD27 and CD28 subsets from CD8+ T cells post-ART (iv). Expression of Maturation and Activation markers on HIV Gag- and CMV pp65-specific T cells (B). CD27 and CD28 expression and CD38 mean fluorescent intensity (MFI) is shown on IFN-γ+ CD8+T cells. (GM = Geometric Mean).</p