Blocking VIP-signaling increased expression of costimulatory molecules and decreased expression of coinhibitory molecules on lymphocytes following mCMV infection.
VIP-KO mice and WT C57BL/6 littermates with 7 daily subcutaneous injections of VIPhyb (starting one day before mCMV infection) or WT littermates treated with PBS were infected i.p. with 1×105 PFU mCMV. Four mice per group were euthanized each time-point at 0, 3, 7, 10 and 17 days post-mCMV infection. The spleens were isolated and phenotypes of activated T-cells and NK cells analyzed by flow cytometry. Data summarized from 3–4 replicate experiments. PD-1 expression on activated CD8+ (A) and CD4+ T-cells (B) following mCMV infection. Data (mean ± SD, n = 12) summarized from 3 replicate experiments. ICOS expression on activated CD8+ (C) and CD4+ (D) T-cells following mCMV infection. Data (mean ± SD, n = 12) summarized from 3 replicate experiments. Effector/memory phenotype CD8+ T-cells (E). Data (mean ± SD, n = 16) summarized from 4 replicate experiments. *p<0.05, **p<0.01, ***p<0.001 denote significant difference compared with WT treated with PBS group.