Fig. 2

Intranasal delivery of adjuvanted RBD_XBB.1.5-HR vaccine induces strong local mucosal immune response. The absolute number of CD8⁺ and CD4⁺ tissue-resident memory T (T_RM) cells in (a) BALF and (b) lung samples from vaccinated mice. T_RM cells were gated on CD44⁺CD62L^-CD69⁺CD4⁺ or CD44⁺CD69⁺CD103⁺CD8⁺ (n = 5 mice each group). c The percentages of antigen specific IFN-γ or TNF-α-producing memory CD8⁺ and CD4⁺ T cells in lung tissue after stimulation with peptide pools for SARS-CoV-2 XBB.1.5 spike (n = 6 mice each group). d The frequencies of T follicular helper cells (CD4⁺PD-1⁺CXCR5⁺), germinal center B cells (CD19⁺GL7⁺CD95⁺), and RBD-specific B cells (RBD⁺CD19⁺) in mediastinal lymph nodes (n = 6 mice each group). The representative images and quantitative analysis of RBD-specific IgG (left) and IgA (right) antibody secreting cells (ASCs) in the (e) lung and (f) spleen tissues (n = 6 mice per group). The middle line indicates the median and the box shows the data range. P values were conducted by One-way ANOVA analysis followed by Tukey’s multiple comparisons test in a–f. ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05; ns not significant