CD8A and neoplasm: Tumor IHC stainingof the CD3 marker revealed significantly increased infiltration ofT cells in the OxPt/SN38 plus αPD-L1 group over other treatmentgroups (Figure 5m).We also detected tumor antigen-specific CD8+ T cells inleukocyte-abundant spleens by an enzyme-linked immunospot (ELISpot)assay (Figure 5k,l).Splenocytes were obtained from MC38 tumor-bearing C57BL/6 mice andstimulated with CD8+ T cell specific epitope KSPWFTTL for48 h.