Early tumor microenvironment events indicate that RV + BTZ combination therapy leads to significantly enhanced immune activation. (A) IHC staining of CD3 in spleens of mice. Note the rare tumor associated CD3⁺ cells in the mice treated with the VC compared with the strong infiltration by such cells in the tumor after treatment with LV and BTZ (magnification ×200 = ×10 and ×20). (B) Bar plots representing quantified CD3⁺ cells in BM and spleen. N = 3; **P < .01, *P < .05, Conover’s test. (C) Bar plots representing quantified CD117⁺ IL22⁺ NK cells in BM. N = 3; **P < .01, *P < .05, Conover’s test. (D) IHC sections of mouse spleens stained for NK cells. IHC staining of CD117⁺ IL22⁺ NK cells in spleens of mice. Note the rare NK cell distribution in LV-treated spleens, robust expression of NK cells in LV + BTZ–treated spleens, and red pulp areas of mouse spleen (magnification ×200 = ×10 and ×20). (A,D) Camera: Ventana Vias Zeiss Axio; acquisition software: Nuance. Composite figure via Adobe Photoshop CS4.