PD-1/CTLA-4 blockade increases T cell tumor infiltration and T cell activation in EBV-infected cord-blood humanized mice.

<p>A) Lymphomas from euthanized untreated EBV-infected cord blood-humanized NSG mice were formalin-fixed and paraffin embedded. Tumors were stained with H&E (10x magnification and 100x magnification), or antibodies for CD20 (B cells), CD8 (cytotoxic T cells), CD4 (helper T cells) and NFATC1 (activated T cell) as indicated. No nuclear NFATC1 staining (indicative of T cell activation) was observed. At least 8 mice were analyzed from each condition and representative figures are shown. B) Lymphomas from EBV-infected cord blood-humanized NSG mice treated with PD-1 and CTLA-4 antibodies were formalin-fixed and paraffin embedded. Tumors were stained with H&E (10x magnification and 100x magnification), or antibodies for CD20 (B cells), CD8 (cytotoxic T cells), CD4 (helper T cells) and NFATC1as indicated. At least 8 mice were analyzed from each condition and representative figures are shown. C) The average number of infiltrating CD4 and CD8 T cells in PD-1/CTLA-4 treated versus untreated tumors was quantitated from 5 different views (60X), using three different tumors for each condition. D) The number of infiltrating FoxP3 positive cells, divided by the number of infiltrating CD4 T cells, was quantitated from 5 different views (60X), using three different tumors for each condition.