Allo-BMT recipients treated with VIP antagonist or transplanted with VIP-KO donors had enhanced primary and secondary antigen-specific cellular immune responses to Lm-MCMV vaccine and mCMV infection. B10BR mice were transplanted with 5 × 106 TCD-BM plus 0.3 × 106 T-cells as described in Figure 1. Twenty-eight days posttransplant, mice were vaccinated with 1 × 106 colony-forming units Lm-MCMV or PBS by i.p. injection and then infected with 1 × 105 mCMV PFU on day +42 posttransplant. (A–B) Survival of transplant recipients treated on day 28 with either PBS (left) or VIPhyb (right). (C-D) Content of tetramer+ CD8+ T-cells in the blood of mice from panels A and B, respectively. (E-J) Percentage tetramer+ CD8+ T-cells expressing PD-1 or CD69. (K-P) Percentage of total CD8+ T-cells expressing CD69 or PD-1. Data are mean values ± standard deviation from 2 replicate experiments with 10 mice per time point. *P < .5, **P < .01, and ***P < .001 signify significant differences comparing mCMV-peptide MHC-tetramer+ CD8+ T-cell levels between VIP-KO or VIPhyb group and WT group.
