Stimulated dendritic cells (DCs) have been shown to be effective in the induction of specific immune cells. Also, the CMV pp65 plays an important role in CMV life cycle and immune recognition. Objective: To assess the effect of CMV pp65 on the maturity and function of dendritic cells In order to design a vaccine or immunotherapy for liver transplant patients.

Splenic DCs were treated with non-cytotoxic concentrations of the pp65 and analyzed for MHC II, CD86, and CD40 expression by flow cytometry. Then, ROR-γ, GATA3, T-bet, and FOXP3 gene expression levels were evaluated in T cells co-cultured with DCs using Real time-PCR. Finally, the effects of pp65 on allogenic T-cell responses in mixed lymphocyte culture (MLR), and the release of cytokines were investigated by ELISA and flow cytometry.

The phagocytosis rate was significantly lower in the pp65-treated DCs than the non-stimulated DCs. There were significant differences in the raised level of CD40, CD86, and CCR7 in DCs as maturation markers. Furthermore, ROR-γ, and T-bet overexpression in T cells of the pp65-treated group compared with the non-stimulated group was observed. Significant differences were observed in the levels of IL-2, IL-6, IL-17, IL-22, TNF-α, and IFN-γ in pp65-stimulated groups compared with the nonstimulated DCs.

The pp65-treated DCs can induce differentiation and functional activity of the cellular immune system, including Th17, and Th1. Therefore, the recombinant pp65 protein can be used as a vaccine or immunotherapy candidate for liver transplant patients.