Involvement of MyD88/Trif signaling in the amplification of CD8⁺ T-cell responses induced by NK-cell targets. (A,B) Frequency of CD8⁺IFN-γ⁺ T cells as measured by restimulation ex vivo 8 days after immunization of wild-type and MyD88/Trif double-deficient mice with either 10⁶ irradiated cells or 10⁶ live act-mOVA.K^b−/− splenocytes (n ≥ 8 for each group). (C) B-cell responses in wild-type and MyD88/Trif double-deficient mice immunized with 10⁶ live act-mOVA.K^b−/− cells as measured by OVA-specific total IgG levels in sera collected 14 days after immunization. (D,E) Activation of OT-I and OT-II cells in wild-type and MyD88/Trif double-deficient mice either in vivo (D) or in vitro (E). (D) Mice were injected with 10⁶ live act-mOVA.K^b−/− cells followed by administration of CD8⁺ OT-I or CD4⁺ OT-II cells intravenously after 3 days. (E) Activation of OT-I and OT-II cells by Flt3L-treated bone marrow–derived DCs from either wild-type or MyD88/Trif double-deficient mice. Proliferation of OT-I and OT-II cells is measured by flow cytometry measuring the dilution of CFSE upon each mother cell division (n = 4). *P ≤ .05; ***P ≤ .001.