Fig. 3

The action of CEACAM1 is intrinsic to T cells. Representative flow cytometry histogram of proliferating CD8⁺ T cells (a) and bar diagram showing percentage of proliferated CD8⁺ T cells (b) from P14 × wild-type (WT) (black line) or P14 × Ceacam1^–/– (red line) mice that were adoptively transferred into WT (CD45.1) mice (1 × 10⁷ cells per mouse) on day −1. Mice were infected with 200 PFU of LCMV-Docile on day 0, and splenic tissue samples were examined 4 days after infection. c Experimental setup. d–f We transferred 1 × 10⁴ P14 × WT or P14 × Ceacam1^–/– (CD45.2) splenocytes into naïve CD45.1 WT mice on day –1 and then infected them with 2 × 10⁴ PFU of LCMV-Docile on day 0, analyzed on day 8 after infection. d Percentage of Tet-GP33⁺ CD45.2⁺ CD8⁺ T cells in blood (n = 6–7) and in spleen (n = 10). e Intracellular cytokine IFN-γ secretion by splenocytes from P14 × WT or P14 × Ceacam1^–/– mice. Horizontal dotted lines designate the detection limit without restimulation (n = 6–7 per group). f Viral titers in indicated organs from CD45.1 WT mice (n = 3–4 per group). g–i Statistical analysis of CD8⁺ T cell population or Tet-GP33⁺ CD8⁺ T cells from murine bone marrow chimeras reconstituted with 1:1 composition of bone marrow from CD45.1 WT:CD45.2 WT mice in one group and bone marrow from CD45.1 WT:Ceacam1^–/– (CD45.2) mice in another group after 45 days of reconstitution before infection, as measured by flow cytometry in blood (g, n = 8 per group), and in blood, spleen, and lymph nodes 8 days after infection with 200 PFU (h) or 2 × 10⁴ PFU (i) of LCMV-Docile (n = 5 per group). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 (Student’s t test). ns = not significant. Data are representative of two (b, g–i), or three (d, e) experiments or one of two independent (a, f) experiments (mean ± SEM; b, d–i)