Fig. 3.

Intranasal immunizations produced higher PA-specific CD8+ T cell responses in lung-draining mediastinal lymph nodes compared with subcutaneous injections. C57BL/6 mice were intranasally or subcutaneously vaccinated with PAQ11. Draining lymph nodes (DLNs) and spleens were collected 10 d after secondary immunization. Antigen-specific memory/effector CD8+ T cells were identified as CD8+ CD44+ PA: H-2Db tetramer+ cells. (A) Representative flow cytometry plots displaying PA-specific CD8⁺ effector/memory (CD44hi) phenotype T cells in DLNs (Top) and spleens (Bottom). Percentages of PA-specific CD8⁺ T cells in DLNs (B) and spleens (C). Group sizes were six (B) or twelve (C) mice, with at least two independent experiments combined, ****: P < 0.0001, ***: P < 0.001. Dose: I.n. or s.c. administration of 50 μL of 2 mM peptide at day 0 and day 28.