PD-1/CTLA-4 blockade increases the number of intra-tumor high endothelial venules, and enhances RANTES production in tumors.

<p><b>A).</b> Lymphomas from EBV-infected cord blood-humanized NSG mice treated with or without PD-1 and CTLA-4 antibodies were formalin-fixed and paraffin embedded, and stained with antibodies for CD20 (B cells), CD8 (cytotoxic T cells), CD4 (helper T cells) and MECA-79 (a marker of high endothelial venules). Arrows are examples of positive staining HEVs. At least 8 mice were analyzed from each condition and representative figures are shown. <b>B).</b> The average number of Meca-79 positive venules in PD-1/CTLA-4 treated versus untreated tumors was quantitated from 5 different views (60X), using seven different tumors for each condition. <b>C).</b> Lymphomas from EBV-infected cord blood-humanized NSG mice treated with or without PD-1 and CTLA-4 antibodies were formalin-fixed and paraffin embedded, and co-stained with antibodies for CD20 (B cells) and RANTES. Arrows are examples of cells staining positive for RANTES and negative for CD20. At least 8 mice were analyzed from each condition and representative figures are shown.