Figure 7.

Treatment of large established CT26 tumours with the anti-MS4A4A mAb improves the therapeutic benefit of anti-PD-1 immunotherapy. (A) qRT-PCR was performed to detect the expression of MS4A4A on TAMs in tumours with different volumes. (B–F) CT26 cells (5×10⁵) were transplanted subcutaneously (s.c.) into BALB/c mice and treated with an isotype control, an anti-PD-1 mAb, an anti-MS4A4A mAb or the anti-PD-1 mAb combined with the anti-MS4A4A mAb when the tumour volume was 300–600 mm³ (n=5/group). (B) Schematic showing the treatment plan. (C) Representative images of CT26 tumours. (D and E) Tumour growth. (F) Tumour weight. (G–K) CT26 cells (5×10⁵) were transplanted s.c. into BALB/c mice and treated with an isotype control, an anti-MS4A4A mAb, anti-PD-1+ anti-MS4A4A mAbs or anti-PD-1+ anti-MS4A4A mAbs combined with RT when the tumour volume was 300–600 mm³ (n=5/group). (G) Schematic showing the treatment plan. (H and I) Tumour growth. (J) Survival of CT26 tumour-bearing mice. (K) Representative images of IHC staining for CD3 and CD8 in tumour sections and statistical analysis. The number of CD3-positive cells and CD8-positive cells per HPF was counted in subcutaneous tumour sections from each group. Five random HPFs were selected for analysis on each slide. HPF, high-power field; IHC, immunohistochemistry; IR, ionizing radiation; i.p., intraperitoneal injection; mAb, monoclonal antibody; mRNA, messenger RNA; PD-1, programmed cell death protein 1; qRT-PCR, quantitative real-time PCR; RT, radiotherapy; TAMs, tumour-associated macrophages.