DOCK8 is necessary for normal NKT effector responses: intact TCR signaling but defective antigen-induced proliferation and cytokine production. (A) WT and DOCK8^cpm/cpm (CPM) mice were examined for cytokine responses 1 hour after injection with αGalCer by staining for CD69 and IFNγ and IL-4 staining by intracellular cytokine staining (upper). Graph (lower) showing the percentage of IFNγ or IL-4 secreting NKT cells in individual mice (circles) with arithmetic means and standard error of the mean. (B) Levels of secreted cytokines from 24-hour cultures of sorted thymic NK1.1⁺ and NK1.1⁻ NKT cells from WT and DOCK8^pri/pri (PRI) mice activated in vitro with plate bound anti-CD3/CD28. Symbols represent replicate measurements with data from 2 independent experiments. (C) Proliferation of CFSE-labeled thymic NK1.1⁺ and NK1.1⁻ NKT cells sorted from DOCK8^pri/pri (PRI, filled) and WT mice (WT, black line) and cultured for 3 days with plate bound anti-CD3/CD28 and αGalCer pulsed dendritic cells. Cell divisions from replicate cultures from 1 experiment with dendritic cells (lower) show arithmetic means and standard deviation. (D) Proliferation of CFSE-labeled thymic NKT cells from WT and DOCK8^cpm/cpm (CPM) mice adoptively transferred into WT mice and immunized with 1 μg αGalCer per mouse. Histograms (top) show NKT cells from WT (black line), DOCK8^cpm/cpm (CPM, filled), and untreated (dotted line) mice after 4 days. Cell divisions (bottom) show arithmetic means and standard deviation. Statistical significance was tested by unpaired t test; *P < .05; **P < .01; ***P < .001.