Myeloid and Plasmacytoid Dendritic Cells Are Susceptible to Recombinant Adenovirus Vectors and Stimulate Polyfunctional Memory T Cell Responses

Abstract

Although replication-incompetent recombinant adenovirus (rAd) type 5 is a potent vaccine vector for stimulating T and B cell responses, high seroprevalence of adenovirus type 5 (Ad5) within human populations may limit its clinical utility. Therefore, alternative adenovirus serotypes have been studied as vaccine vectors. In this study, we characterized the ability of rAd5 and rAd35 to infect and induce maturation of human CD11c+ myeloid dendritic cells (MDCs) and CD123+ plasmacytoid dendritic cells (PDCs), and their ability to stimulate Ag-specific T cells. Both MDCs and PDCs were found to express the primary receptor for Ad35 (CD46) but not Ad5 (coxsackie-adenovirus receptor; CAR). Both dendritic cell (DC) subsets were also more susceptible to rAd35 than to rAd5. MDCs were more susceptible to both rAd35 and rAd5 than were PDCs. Whereas rAd35 used CD46 for entry into DCs, entry of rAd5 may be through a CAR-independent pathway. Exposure to rAd35 but not rAd5 induced high levels of IFN-α in PDCs and phenotypic differentiation in both DC subsets. MDCs and PDCs exposed to either rAd5 or rAd35 encoding for CMV pp65 were able to present pp65 and activate CMV-specific memory CD8+ and CD4+ T cells in a dose-dependent manner, but MDCs stimulated the highest frequencies of pp65-specific T cells. Responding T cells expressed multiple functions including degranulation (CD107a surface mobilization) and production of IFN-γ, IL-2, TNF-α, and MIP-1β. Thus, the ability of rAd35 to naturally target important DC subsets, induce their maturation, and appropriately present Ag to T cells may herald greater in vivo immunogenicity than has been observed with rAd5.

Adenovirus serotype 5 infects human dendritic cells via a coxsackievirus–adenovirus receptor-independent receptor pathway mediated by lactoferrin and DC-SIGN

“…This study was approved by the ethical committee at the Karolinska Institutet, Stockholm, Sweden, and the NIH, Bethesda, MD, USA. Our sorting procedures for direct isolation of DCs from blood have been described previously (Lore et al, 2003(Lore et al, , 2007Smed-Sorensen et al, 2005). DCs were cultured in complete medium composed of RPMI 1640 and 10 % fetal calf serum (FCS; Sigma-Aldrich).…”

“…We exposed the cell populations to an inoculum of 100 i.p. rAd5-GFP per cell and analysed the frequency of infected cells after 24 h by flow cytometry as described previously (Lore et al, 2007). Among the APCs purified from blood, MDDCs, monocytes and MDCs were susceptible to rAd5, whilst PDCs showed markedly lower infection frequencies (Fig.…”

“…We have previously demonstrated that primary human CD11c + myeloid DCs (MDCs) and CD123 + plasmacytoid DCs (PDCs) are susceptible to rAd5 and are able to present rAd5-encoded antigen to activate specific T-cell responses (Lore et al, 2007). In this study, we investigated the involvement of CAR and the influence of Lf in rAd5 infection in relevant primary human APC populations from both blood and skin.…”

“…However, CAR is naturally expressed in tight junctions between cells and therefore has limited accessibility on the apical cell surface (Cohen et al, 2001). As a likely consequence of this, CAR has been shown to play a minor role in Ad5 infection of epithelial cells (Johansson et al, 2007), hepatocytes (Smith et al, 2003), fibroblasts (Hidaka et al, 1999;Leopold et al, 2006) and antigen-presenting cells (APCs) such as dendritic cells (DCs) (Cheng et al, 2007;Lore et al, 2007;Rozis et al, 2005;Tillman et al, 1999). Thus, CAR-independent infection pathways used by Ad5 have been proposed.…”

Augmentation of adenovirus 5 vector-mediated gene transduction under physiological pH conditions by a chitosan/NaHCO3 solution

“…These cell lines do not express CAR. [31][32][33] We found that both b-galactosidase activity assay (Figure 5a) and X-gal staining (Figure 5b) indicated that chitosan/NaHCO 3 treatment enhanced AMGT compared with Ad5-LacZ alone in these cell lines. The efficacy was highest in the DC2.4 cells (24-fold) and lowest in the RD cells (8-fold; Figure 5a).…”