Figure 3.

Modulation of MHC class I antigen expression and T cell infiltration by 5-AZA-CdR combined with mAb 9H10 in the syngeneic TS/A mouse tumor model. BALB/c mice were inoculated sc with 2 × 10⁵ TS/A cells. Groups of 5 mice were injected ip with 5-AZA-CdR; with mAb 9H10; with combined administration of 5-AZA-CdR and mAb 9H10 according to the above reported schedules, or with saline solution for control. A week after the end of treatment, neoplastic and normal tissues were excised and snap frozen in liquid nitrogen. Four micron acetone-fixed cryostat sections were processed for IHC assays. Representative results from tumors (A–F) and normal tissues (G–N) are reported. (A– C): MHC class I staining of tumors from mice treated with saline solution, with mAb 9H10 or 5-AZA-CdR, respectively; (D– F): CD3 staining of tumors from mice treated with saline solution, with mAb 9H10 or the combination of 5-AZA-CdR and with mAb 9H10, respectively; (G–I and L–N): CD3 staining of glandular epithelium of large intestine, liver, lung, myocardium renal parenchyma and dermis from mice treated with mAb 9H10 or 5-AZA-CdR, respectively. (A–F), 200× magnification, (G–M), 160× magnification; (N), 250× magnification. The arrowed marks the dermal-epidermal junction; black arrows, CD3⁺ lymphocytes.