Figure 3.

Immunohistochemistry showed marked differences in T-cell infiltration (CD4⁺, CD8⁺) and activation (Granzyme B⁺) leading to differentiation to Desmin⁺ cross striated muscle cells as shown exemplarily in (A). T cell infiltration and activation were pronounced in the tumors treated with a combination of NHS-IL12 and irradiation. Whereas hardly any infiltration was observed in the contralateral tumors of the irradiation only group, the animals of the NHS-IL12 and irradiation group with extensive infiltrates in the ipsilateral tumors showed also infiltrates contralaterally. Desmin⁺, differentiated areas were predominantly present in tumors treated with the combination regime (B). Tumor size at day 15 differed significantly for tumors with T-cell infiltrates (CD4^high and CD8^high) as well as for Granzyme B^high tumors (C). For survival analysis, animals were scored with the higher IHC scoring of both tumors and stratified as “high” or “low.” T-cell infiltration (CD4^high, CD8^high) correlated with tumor-size-specific survival, whereas T cell activation (Granzyme B^high) showed no significant correlation with survival (D).