Figure 1.

GPR174 constrains T cell proliferation in vivo. (a) To assess homeostatic proliferation, a 1:1 mixture of wild-type (CD45.1/2⁺; shaded gray plots) and either wild-type (CD45.2⁺; upper left panel; open solid line) or Gpr174^−/Y (CD45.2⁺; lower left panel; open solid line) naive CD8⁺ T cells were labeled with CFSE. A total of 1×10⁶ T cells were transferred into CD45.1⁺ recipient mice that had been irradiated the day before with 600 cGy irradiation. Homeostatic proliferation was assessed based on the CFSE dilution profile (left) and ratio of wild-type to wild-type or Gpr174^−/Y cells recovered in the spleen of recipient mice seven days after transfer was determined (right). (b–c) To assess endogenous T cell proliferation in a Treg cell ablation model, cohorts of wild-type and Gpr174^−/Y mice that expressed a Foxp3-DTR transgene were treated with diphtheria toxin intrapetironeally with an initial dose of 20 μg kg⁻¹ on day 0, and then with 5 μg kg⁻¹ on days 2 and 4. Spleen weights (b) and numbers of CD4⁺ and CD8⁺ T cells in the spleen (c) were quantified on day 7; * P < 0.05; ** P < 0.01. Data are representative of two independent experiments; each dot represents a mouse.