CD8⁺ T-cell priming upon administration of K^b-deficient or allogeneic NK-cell targets is highly sensitive. CD8⁺ T-cell responses upon administration of various doses of K^b-deficient (A,B) or allogeneic (C-D) NK-cell targets. CD8⁺ T-cell responses were quantified 8 days after immunization by measuring IFN-γ production upon restimulation with OVA_257-264 ex vivo (A) or the ability of CD8⁺ T cells to kill OVA-expressing target cells in vitro (B). (C,D) C57BL/6 mice were either immunized with act-mOVA targets on a mixed H-2^b × H-2^k (closed bars) or H-2^b × H-2^d (open bars) background (± SEM; n = 3). (E) Survival of allogeneic C3H/HeN-act-mOVA and β₂m-deficient splenocytes in C57BL/6J recipient mice (percentage is calculated from the ratio between β₂m-deficient and C57BL/6J cells in β₂m-deficient recipients for each day). (F) CD8⁺ T-cell responses upon administration of 10⁶ allogeneic C3H/HeN.act-mOVA target cells in C57BL/6J control, C57BL/6J-Prf1^tm1Sdz, and C57BL/6J^gld/gld recipient mice (n = 6 for each group).