PMC

CRTAM deficiency results in an impaired IL-17 production by T cells. WT and Crtam^−/− mice were infected orally with 10 cysts of T. gondii strain ME49. Frequencies of (A) intraepithelial and (B) lamina propria IFN-γ, IL-17, and IL-22 producing CD4⁺ T cells were analyzed at days 5 and 8 post-infection. (C) Expression of Ifng, Il17a, Il17f, Il22, and Il10 in the ileum of infected mice analyzed by quantitative PCR at days 5, and 8 post-infection. Bars represent means, error bars represent SEM. Data are representative of two independent experiments (n = 4). Statistical analysis was performed using Student's t-test (*p < 0.05; **p < 0.01; ***p < 0.001).

Th17 lineage specification is CRTAM-independent. WT and Crtam^−/− mice were infected orally with 10 cysts of T. gondii strain ME49. (A) Representative flow cytometry plots showing percent of rorγt of CD4 T cells and foxp3 and rorgt expression on CD4 T cells. (B) frequencies of Rorγt⁺ T cells and (C) Rorγt⁺Foxp3⁺ T cells in the small intestinal lamina propria of infected mice at day 5. Bars represent means, error bars represent SEM. Data are representative of two independent experiments (n = 3). Statistical analysis was performed using Student's t-test.

IL-17 blockade curbs AMP production and augments bacterial translocation. WT mice were injected intraperitoneally with 350 μg of anti-IL-17A and anti-IL-17F or an isotype control (I.C.) at days −1 and 5 and infected orally with 10 cysts of T. gondii strain ME49. (A) Expression of S100a8, S100a9, Defb3, and Reg3g mRNA in the ilea of infected mice at day 8 determined by quantitative PCR. Bacterial counts present in the (B) mesenteric lymph node and (C) spleen at day 8 post-infection. Bars represent means, error bars represent SEM. Data are representative of two independent experiments (n = 4). Statistical analysis was performed using Student's t-test (*p < 0.05).

Crtam^−/− mice are more susceptible to pathology during T. gondii infection. WT and Crtam^−/− mice were infected orally with 10 cysts of T. gondii strain ME49, uninfected mice were used as control. (A) Survival (B) weight loss, and (C) parasite burden were analyzed at the indicated time points. (D) Representative sections of ileum stained with hematoxylin and eosin and (E) histological score in naïve mice and at day 8 post-infection. Symbols and bars in (A,B,E) represent means, error bars represent SEM. Symbols in (C) represent single mice. Data are representative of two independent experiments (n = 4–5). Statistical analysis was performed using Student's t-test or Log-rank Mantel-Cox test for survival curves (*p < 0.05; ***p < 0.001).

Absence of CRTAM expression results in impaired antimicrobial peptide production. WT and Crtam^−/− mice were infected orally with 10 cysts of T. gondii strain ME49. (A) Expression of S100a8, S100a9, Defb3, Reg3g, Defa1, and Defa2 mRNA in the ilea of infected mice at days 0, 5, and 8 determined by quantitative PCR. 16S rRNA sequencing of ileal lumen contents at day 0 or 8 days post-infection (D8). Data are mean bacterial changes at the (B) phyla or (C) order level, and (D) principal coordinates analysis on weighted UniFrac distances (n = 4). Bacterial counts present in the (E) mesenteric lymph node and (F) spleen at day 8 post-infection. Bars represent means, error bars represent SEM. Data are representative of two independent experiments (n = 4–8). Statistical analysis was performed using Student's t-test (*p < 0.05; **p < 0.01; ***p < 0.001).