SK6005 skin tumor tissues were fixed and embedded in paraffin, and 4 µm sections were prepared for staining. Immunohistochemical staining was performed with primary antibodies specific for CD4 (Sino Bio 50134-R001), CD8 (Affymetrix 14–0808), and FoxP3 (Novus NB100–39002) on the Bond RX system (Leica Biosystems, Germany). Briefly, the sections were processed by the following incubation steps: Bond dewax solution (Leica AR9222), 0.5 min at 72 °C; Bond epitope retrieval solution 1 (Leica AR9961) or Bond epitope retrieval solution 2 (Leica AR9640), 20 minutes at 100 °C; Bond wash buffer (Leica AR9590), 3 minutes at room temperature (RT); peroxide block (Leica DS9800), 10 minutes at RT; goat serum, 20 minutes at RT for the anti-CD8 antibody; primary antibody, 60 minutes at RT; Bond wash buffer, 3 times for 2 minutes each at RT; polymer, 20–30 minutes at RT; Bond wash buffer, 3 times for 2 minutes each at RT; DAB (Leica DS9800), 5 minutes at RT; and hematoxylin (Leica DS9800), 10 minutes at RT. Five fields in each stained sample without necrosis were randomly selected and imaged at 20× magnification. All images were analyzed with ImageJ software. Positive cells were counted, and the average number of positive cells in 5 fields was taken as the score value of each sample.
Wang Z., Sun K., Xiao Y., Feng B., Mikule K., Ma X., Feng N., Vellano C.P., Federico L., Marszalek J.R., Mills G.B., Hanke J., Ramaswamy S, & Wang J. (2019). Niraparib activates interferon signaling and potentiates anti-PD-1 antibody efficacy in tumor models. Scientific Reports, 9, 1853.
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