CD8A and melanoma: Using dextramer staining to detect endogenous T cells specific for H-2Kb–SIINFEKL in the dLN 72 h after tumour engraftment, we detected higher numbers and proportions of antigen-specific CD44+CD8+ T cells when tumour inoculation was performed at ZT9 compared with ZT21 in both the melanoma and mammary carcinoma models (Fig. 2e and Extended Data Fig. 4e).