A Self-Help Program for Memory CD8+ T Cells: Positive Feedback via CD40-CD40L Signaling as a Critical Determinant of Secondary Expansion
Figure 6
Accelerated clearance of homologous vaccine vector limits inflammation and correlates with increased CD40L dependence.
(A–B) Mice were primed with 107 cfu Lm-OVA, 106 pfu VV-OVA, or HBSS and boosted 21 days later with 107 cfu Lm-QV (n = 5). (A) Spleens and livers were harvested at 24, 48, and 72 hours following boost, and cfu were enumerated by plating organ homogenates (mean, ±SEM). (B) Serum cytokine levels at 4 and 24 h following boost (mean, ±SEM). (C–E) Mice were primed with 107 cfu Lm-OVA or 106 pfu VV-OVA and boosted 21 days later with 5 µg DEC205-OVA alone, 5 µg DEC205-OVA with 105 cfu Lm-OVA, or HBSS. αCD40L or control antibody was administered to the indicated groups during boost. OVA257–264-specific memory CD8+ T cell responses were assessed 5 days post-boost using intracellular cytokine staining for IFN-γ (n = 5). (C) Representative plots of OVA257–264-specific T cell enumeration (median shown, ±SEM). (D) Total OVA257–264-specific (IFN-γ+) CD8+ T cells per animal (mean, ±SEM). *, P<0.05, **, P<0.01, ***, P<0.001, ANOVA. Data are representative of two independent experiments.