Effects of clone 19 and nivolumab derivatives on the antigen-specific expansion of humanized vs. WT PD-1 expressing and non-expressing CD4 T cells from OT-II mice following immunization with ovalbumin. A 50:50 mix of cells was injected into recipient mice on day 0, which were then immunized intraperitoneally (IP) with 100 g of ovalbumin on day 1 and treated IP with 200 g of isotype control or PD-1 antibodies on day 2. The ratio of cells in the spleens of the mice on day 8, quantified by flow cytometry and normalized to the average ratio in isotype control treated mice (dashed line), is shown.
