CD8A and neoplasm: P14 CD8+ Teff cells exposed through transwells to soluble mediators released by CD28KOCD8+ T cell were less effective than those exposed to that by CD28WTCD8+ in controlling tumor growth (Fig. 1k) and mice receiving P14 CD8+ Teff cells exposed to soluble mediators from CD28KOCD8+ T cells had significantly poorer survival than those exposed to that from CD28WTCD8+ (Fig. 1l).