Figure 2. T cell responses to tumor antigens are generated but not sustained.

(A) Representative analysis of SIY and SIN specific CD8⁺ T cells in the lung and the draining mediastinal lymph node (DLN) of Lenti-x or Lenti-LucOS tumor-bearing mice or WSN-SIY infected mice using peptide-loaded K^b reagents. FACS plots are gated on PI-negative, CD8⁺ cells.

(B and C) Percent of lymphocytes specific for SIN or SIY during Lenti-LucOS tumor progression in the lung or DLN. The percent of anti-SIN or anti-SIY reactive cells (of total lymphocytes) was determined as shown in Figure S2A. n= 2–5 mice per time-point.

(D) IFNγ and TNFα cytokine production in SIY and SIN-reactive T cells from the lungs of Lenti-LucOS tumor-bearing mice at several time points after tumor initiation. The percentage of SIY and SIN-specific T cells from the lungs that were IFN-γ⁺TNF-α⁺ or IFN-γ⁺TNF-α^neg in the absence (no peptide) or in the presence of SIY and SIN peptides (+ peptide) is shown. Percentages were determined by staining duplicate samples for either DimerX or cytokine production as described in Figure S2L. n= 2–7 mice per time-point.

(E) The percentage of SIY and SIN-specific T cells in the DLN that were IFN-γ⁺TNF-α₊ 16 weeks after tumor initiation with Lenti-LucOS or WSN-SIY infection. n= 4 mice per group.

(F) PD-1 surface expression on anti-SIY/K^b+ and anti-SIN/K^b+ CD8⁺ cells (open histograms) or non-specific CD8⁺ cells (filled histograms) from the lungs of Lenti-LucOS tumor-bearing mice at several time-points after tumor initiation. n= 2–3 mice per group.

Data are mean ± SEM. See also Figure S2.