T_EMs are defective in their ability to produce cytokines and induce lower levels of TNF-α and IFN-γ in recipients. B6 CD45.1 mice were irradiated and reconstituted with TCD B6^bm12 BM with either 10⁶ B6^bm12 CD4⁺ T_EMs or 5 × 10⁵ CD4⁺ T_Ns. (A) Representative staining for intracellular IFN-γ and IL-2 in donor-derived CD45.1⁻CD4⁺ cells in spleens harvested day +7 after BM transplantation. Numbers on plots are the percentages of total cells in the rectangles. (B) Total number of donor CD4⁺Thy1.2⁺ cells in spleen on day +7 (left panel; P = .002) and the percentage of these that stain for intracellular IFN-γ (right panel; P = .001). Each symbol represents data from an individual mouse; the horizontal line is the mean. (C) Mice were bled on days +5, +7, and +10, and serum levels of IFN-γ and TNF-α were measured by Luminex technology. Recipients of T_Ns (relative to T_EMs) had higher serum levels of IFN-γ (day +7; P < .001) and TNF-α (days +7 and +10; P = .002 and P = .015, respectively). Error bars represent SD.