Extended Data Fig. 7: CD4+ T cells are essential for chemokine production and accumulation of CD8+ T cells and moDCs at the mucosal site.
a, Schematic of the experimental setup showing C57BL/6J mice were i.m. immunized with mRNA-LNPs at day 0, i.n. boosted with an unadjuvanted SARS-CoV-2 spike protein at day 15, i.n. treated with PBS or a CD4 depleting antibody at days 14 and 16, followed by lung and BALF collection at day 2 post intranasal boosting. b, ELISA measurements of CXCL9 and CXCL10 concentrations in BALF of naïve C57BL/6J mice (n = 5); intramuscularprime-only mice (D17P, n = 4) and intranasalbooster-only mice (D17S, n = 5) at day 17 post-priming; P + S PBS-treated mice (D17PBS, n = 10); P + S CD4 depleting antibody-treated mice (D17Ab, n = 9) at day 17 post-priming as in a. Detection limits, CXCL9 (0.23 pg/mL) and CXCL10 (0.63 pg/mL). c, Representative flow cytometry plots and quantification of the number of extravascular IV–CD8+ T cells and IV–CD44+Tet+CD8+ T cells in the lung of intramuscular prime-only mice (D17P, n = 4) and intranasal booster-only mice (D17S, n = 5) at day 17 post-priming; P + S mice treated with PBS (D17PBS, n = 6) or CD4-depleting antibody (D17Ab, n = 8) at day 17 post priming as in a. d, Representative flow cytometry plots and quantification of the number of total and Ly6C+ moDCs in the lung from mice as in c. Mean ± SEM. Statistical significance was calculated by one-way ANOVA (b-d). Tukey’s multiple comparisons were performed; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Data were pooled from two (b-d) independent experiments. Values indicated as zero show the absence of detectable cells (c,d).
