Fig. 2: Prophylactic vaccination of MAIT cells delays the priming of Mtb-specific CD4 T cells in a MR1-dependent manner.

a WT mice were treated intrapharyngeally (iph) with 1 μM 5-OP-RU, 10 μg of CpG, or both (in 30 μl of PBS per mouse). Lungs were harvested 6 days after treatment. Representative FACS plots of MR1/5-OP-RU tetramer staining of Thy1⁺ cells (b) and number of MAIT cells (c) in the lungs from mice treated as shown in a. Representative FACS plots (d) and frequency (e) of IL-17A⁺, TNF⁺, or IFN-γ⁺ lung MAIT cells after treatment with CpG ± 5-OP-RU. f WT mice were iph treated with CpG ± 5-OP-RU 6 days prior to aerosol Mtb infection and lungs were harvested on day 35 postinfection (p.i.). g Bacterial CFU in the lungs from mice treated as shown in f. h WT mice were iph treated with CpG ± 5-OP-RU 6 days prior to aerosol Mtb infection and received intravenously CFSE-labeled C7 transgenic (Tg) CD4 T cells on day 5 p.i. Lungs and mediastinal LN (mLN) were harvested on day 14 p.i. Bacterial CFU in the tissues (i), representative histograms of CFSE dilution (j), and number (k) of C7 CD4 T cells in the mLN from mice treated as shown in h. l CFSE-labeled C7 CD4 T cells were adoptively transferred into WT or MR1^−/− mice 1 day before aerosol Mtb infection and tissues were harvested on day 10 p.i. m–o Bacterial CFU in the tissues (m), representative histograms of CFSE dilution (j), and number (k) of C7 CD4 T cells in the mLN from mice treated as shown in l. p CFSE-labeled C7 CD4 T cells were adoptively transferred into WT mice prior to iph infection with Mtb. Mice were treated with isotype or anti-MR1 antibody at the time of infection and 5 days p.i. Tissues were harvested on day 10 p.i. Bacterial CFU in the tissues (q), representative histograms of CFSE dilution (r), and number (s) of C7 CD4 T cells in the mLN from mice treated as shown in p. Date are pooled from two independent experiments with three or more mice per group. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.