Figure 6. LMTAG immunization promotes the progenitor TST population. (A) Scheme Early AST;Cre-ERT2 were adoptively transferred with TCRTAG at age 42 days and immunized at age 80 days with LMTAG. 60 days later, LY108+CD8+ Thy1.1+ TCRTAG were sorted from the spleen, transferred into secondary AST;Cre-ERT2 hosts and analyzed 8 days later. (B) Left, TNFα or IFNγ production after 4 hour ex vivo TAG peptide stimulation plotted against TCF1 in TCRTAG isolated from the spleens of LMTAG-immunized 1° hosts. Right, percentage of TCF1 positive and negative cytokine-producing TCRTAG. Each symbol represents an individual mouse with n=10/group. ****p<0.0001 (Student’s t-test). (C) Left, LY108 expression of presort and postsort splenic TCRTAG from LMTAG-immunized mice. Middle, TCF1 and TOX expression (top), and CD39 and PD1 expression (bottom) of presort and postsort LY108hi TCRTAG. Right, TCF1 and TOX expression (top), and CD39 and PD1 expression (bottom) from TCRTAG retrieved from spleen and liver of secondary hosts. (D) From left to right, percentage of TCF1+, TOX+, and PD1+CD39+ of presort LY108hi TCRTAG and post-transfer (tx) TCRTAG isolated from spleens or livers of secondary AST;Cre-ERT2. For (C, D), n=4 primary and secondary hosts, representative of 2 independent experiments. *p<0.05, **p<0.01, ****p<0.0001 (one-way ANOVA followed by post hoc Tukey test). ANOVA, analysis of variance; LM, Listeria monocytogenes.
