Figure 2. Endogenous T1-type CD4+ and CD8+ T-cells are required by CY+TLRa-treated hosts to induce sustained tumor rejection.

A. Tumor growth curves of WT 4T1 TB BALB/c mice variably depleted of CD4+ and/or CD8+ T-cell subsets, and treated with CY+CpG. Using two-tailed Fisher's exact test (durable tumor regression, yes or no), treatment without T-cell depletion was significantly different from groups receiving anti-CD4 (**p < 0.01), anti-CD8 (**p < 0.01) or both (***p < 0.001) depleting mAbs. Data in panel 2A are illustrative of 2 independent biological replicates in the 4T1 model (n = 5-12 mice per each condition in displayed experiment) and endogenous T-cell dependence was also observed in the CT26 and Panc02 models (data not shown). B. Athymic nude mice received either naïve WT T-cells, naïve IFNγ KO T-cells or none prior to 4T1 challenge. Subsequently, mice variously received treatment with CY+CpG or CY+CpG+IFNγ for 7 cycles. 4T1-TB nude mice treated with the CY+CpG regimen completely failed to reject tumor challenges in the absence of T-cell transfer. Compared to untreated mice, significant rescue of CY+TLRa's capacity to produce durable tumor rejections was observed with adoptive transfer of WT T-cells (**p < 0.01), but not with IFNγ KO T-cells (ns, p = 0.4667) or exogenous IFNγ (ns, p = 0.1923). Data in panel 2B demonstrating dependence of CY+TLRa treated nude mice upon adoptive receipt of IFNγ-producing splenocytes (not shown) or purified splenic T-cells (shown) are illustrative of 2 independent biological replicates in the 4T1 model (n = 5-8 mice per each condition in displayed experiment). Statistical comparisons in both 2A and 2B panels were performed using two-tailed Fisher's exact test. ns = non-significant.