Synergistic Reversal of Intrahepatic HCV-Specific CD8 T Cell Exhaustion by Combined PD-1/CTLA-4 Blockade (original) (raw)
Figure 6
The functional response to PD-1/CTLA-4 blockade associate directly with CTLA-4 expression but not FoxP3+ Tregs.
(A) Correlation between HCV specific effector cytokine response to combined PD-1/CTLA-4 blockade and ex vivo %CTLA-4+/CD8 but not %PD-1+/CD8 and %FoxP3+/CD4. The y-axis represents the sum of CD8 T cells with HCV-specific IFN-γ+TNF-α+, IFN-γ+TNF-α− and IFN-γ−TNF-α+ expression during combined PD-1/CTLA-4 blockade from 14 HLA-A2− patients (6 intrahepatic and 8 peripheral blood responses). R and p-values by the Spearman rank correlation test. (B) Positive correlation between fold expansion of HCV-specific tetramer+ CD8 T cells with combined PD-1/CTLA-4 blockade (relative to PD-1 blockade alone) and ex vivo %CTLA-4+ in HCV-specific tetramer+ CD8 T cells in 7 HLA A2+ HCV-infected patients. R- and p-values by the Spearman rank correlation test. (C) (Left): Liver infiltrating lymphocytes from chronic patient C07 are examined for CD4, CD8 and FoxP3+ T cell subsets before (upper) and after (lower) depletion of CD4 T cells by CD4 Dynabeads (Dynal Inc), resulting in >99% depletion of CD4 T cells including FoxP3+ CD4 T cells. (Right): Undepleted and CD4-depleted liver infiltrating lymphocytes were cultured for 7 days with overlapping HCV NS3-derived 15mer peptides (pNS3) in the presence of isotype or blocking antibodies before direct staining for T cell subsets (CD4, FoxP3) and following additional 6 hours of stimulation with media alone (negative control) or pNS3 peptides to examine HCV-specific intracellular IFN-γ and TNF-α expression in CD8 T cells. Combined PD-1/CTLA-4 blockade promoted markedly enhanced HCV-specific cytokine response in undepleted and CD4-depleted cultures regardless of FoxP3+ Tregs.