Fig. 1.

The immunosuppressive microenvironment in murine EGFR^L858R –induced lung adenocarcinomas is partially reversed by erlotinib. (a) Experimental outline of tumor induction and erlotinib treatment. CCSP-rtTA; TetO-EGFR^L858R mice and littermate controls on a doxycycline diet (green arrow) for 6–7 weeks were treated with erlotinib or left untreated for 2 weeks. Infiltrating immune cells were analyzed by flow cytometry. Quantification of (b) CD4 and CD8 T cells (c) FoxP3 positive CD4 T cells (d) T_reg/ CD8+ T cell ratio and (e) PD-1 positive FoxP3- and FoxP3+ CD4 and CD8 T cells in the lungs (and spleens) of normal lung (NL) and tumor bearing CCSP-rtTA; TetO-EGFR^L858R mice in the absence (−) and presence (+) of erlotinib for 2 weeks. Data are obtained from three independent experiments, (n = 4–6 mice per group). Data are shown as mean ± SD and * is P < 0.05 in a student’s t-test