Combination immunotherapy with IL-2 surface-modified tumor cell vaccine and PD-1 blockade against renal cell carcinoma.

Immunotherapy may be an effective way to prevent postoperative recurrence of renal cell carcinoma. Streptavidin-interleukin-2 (SA-IL-2) surface-modified tumor cell vaccine developed through our protein-anchor technology could induce specific antitumor T-cell responses, but this immunotherapy cannot completely eradicate the tumor. These effector T cells highly expressed programmed death receptor-1 (PD-1), and the expression of programmed death ligand-1 (PD-L1) in the tumor environment also was upregulated after SA-IL-2-modified vaccine therapy. PD-1/PD-L1 interaction promotes tumor immune evasion. Adding PD-1 blockade to SA-IL-2-modified vaccine therapy increased the number of CD4(+), CD8(+) and CD8(+)interferon-gamma(+) but not CD4(+)Foxp3(+) T cells. PD-1 blockade could rescue the activity of tumor-specific T lymphocytes induced by the SA-IL-2-modified vaccine. Combination therapy delayed tumor growth and protected mice against a second Renca cells but not melanoma cells challenge. Taken together, PD-1 blockade could reverse immune evasion in the treatment with SA-IL-2-modified vaccine, and eventually induce a stronger specific antitumor immune response against renal cell carcinoma.