Fig. 3: Naïve and memory T cells remain functional following sAg activation.

a 5 × 10⁶ naïve F5.CD45.1⁺ CD8⁺ T cells activated in vitro with either NP-peptide or 0.1% v/v JKD6159::sea bacteria supernatant were seeded into B6 mice and were left to rest for 10 days. Representative flow cytometry profiles showing the level of expression of CD44, CD69 and CD62L on the peptide and sAg activated F5.CD45.1⁺ cells prior to transfer compared to unstimulated naïve cells (grey contours). Graph depicts the proportion of F5⁺ CD8⁺ T cells expressing CD44, CD69 and CD62L following peptide or sAg activation. Bars represent the mean ± SEM, and symbols represent individual cultures. Data pooled from 10 experimental cultures. b The proportion of Tem (CD62L⁻) and Tcm (CD62L⁺) F5.CD45.1⁺ CD8⁺ T cells in the spleen and mLN. Bars represent the mean ± SEM (n = 2 or 4 mice per group). c Mice generated as described in a or mice receiving 5 × 10⁶ naïve F5.CD45.1⁺ CD8⁺ T cells were either left untreated (d0) or were infected intranasally with 10⁴ PFU X31(DAM) and 7 days later the absolute number of F5.CD45.1⁺ CD8⁺ T cells in the spleen and lung were measured. Symbols represent individual mice, bars represent the mean ± SEM (n = 4–11 mice per group, Two-way ANOVA, Tukey’s multiple comparison). The proportion of F5.CD45.1⁺ T cells in the (d) lung and (e) spleen producing TNFα and/or IFNγ following a brief in vitro stimulation was measured by flow cytometry. Bars represent the mean ± SEM, and symbols represent individual mice (n = 5–11 mice cohort, Two-way ANOVA, Sidak’s multiple comparison). f–h 5 × 10⁶ naïve or memory F5.CD45.1⁺ CD8⁺ T cells activated in vitro with either NP-peptide or 0.1% v/v JKD6159::sea bacteria supernatant were seeded into B6 mice and were left to rest for 10 days were infected intranasally with 10⁴ PFU X31(DAM) (f) Representative flow cytometry profiles showing the level of expression of CD69 and CD62L on the peptide and sAg activated memory F5.CD45.1⁺ T cells prior to transfer. g Representative flow cytometry profiles of the lung on day 7 post infection (h) The absolute number of F5.CD45.1⁺ CD8⁺ T cells in the spleen and lung were measured on day 7 post infection. Symbols represent individual mice, bars represent the mean ± SEM (n = 4 or 5 mice per group, Two-way ANOVA, Tukey’s multiple comparison). *p < 0.5, **p < 0.01, ***p < 0.001, and ****p < 0.0001.