MAPK1 and neoplasm: Splenocytes from mutated (m) ERK2 peptide (a H-2Kd-restricted epitope for CMS5a tumour cells)-specific TCR gene-transgenic DUC18 mice22 or BALB/c mice splenocytes were cultured, and the supernatants were used as a source of EVs from tumour-specific or nonspecific CD8+ T cells, respectively (Supplementary Fig. 1a: DUC18 CD8 EV or BALB CD8 EV).