ΔY mice are deficient in generating specific CD8 T cell responses following <i>Listeria</i>-OVA infection.

<p>K^bWT and ΔY mice were orally infected with 5e⁷ or 1e⁶ cfu <i>Listeria</i>-OVA or mock infected with 0.1 M HEPES-PBS. Spleens and MLN were harvested 9 days post infection and analysed directly <i>ex vivo</i> or specific T cells were expanded in culture by incubation with OVA_(257–264) peptide A, Cytotoxicity assays were performed whereby OVA_(257–264) peptide pulsed, sodium chromate-labeled target cells were incubated with restimulated effector T cells from spleens of infected mice. The ability of effector T cells to lyse targets was measured as chromium release at indicated ratios. 2 mice per group were analysed for each dose of infection tested. Cytotoxicity experiments were performed in triplicate. B, C, <i>Listeria</i>-derived OVA_(257–264)-specific CD8 T cells from spleens or MLN of 2 mice per group were quantified by tetramer staining following oral infection with 5e⁷ cfu <i>Listeria</i>-OVA and restimulation of the T cells <i>in vitro</i> (B) or analysed directly <i>ex vivo</i> (C). <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007210#s2" target="_blank">Results</a> are presented as bar graphs of fold increases in % tetramer/CD8 T cells stained plus SD; Student's <i>t</i> test *, <i>p</i><0.05.