Incorporation of Porcine Adenovirus 4 Fiber Protein Enhances Infectivity of Adenovirus Vector on Dendritic Cells: Implications for Immune-Mediated Cancer Therapy

Abstract

One strategy in cancer immunotherapy is to capitalize on the key immunoregulatory and antigen presenting capabilities of dendritic cells (DCs). This approach is dependent on efficient delivery of tumor specific antigens to DCs, which subsequently induce an anti-tumor T-cell mediated immune response. Human adenovirus serotype 5 (HAdV5) has been used in human studies for gene delivery, but has limited infection in DCs, which lack the proper receptors. Addition of the porcine fiber knob (PK) from porcine adenovirus type 4 to HAdV5 allows the virus to deliver genetic material via binding to glycosylated surface proteins and bypasses the coxsackie-and-adenovirus receptor required by wild-type HAdV5. In this study we explored the potential therapeutic applications of an adenovirus with PK-based tropism against cancers expressing mesothelin. Infectivity and gene transfer assays were used to compare Ad5-PK to wild-type HAdV5. Mouse models were used to demonstrate peptide specificity and T-cell responses. We show that the PK modification highly augmented infection of DCs, including the CD141+ DC subset, a key subset for activation of naïve CD8+ T-cells. We also show that Ad5-PK increases DC infectivity and tumor specific antigen expression. Finally, vaccination of mice with the Ad5-PK vector resulted in enhanced T-cell-mediated interferon gamma (IFN-γ) release in response to both mesothelin peptide and a tumor line expressing mesothelin. Ad5-PK is a promising tool for cancer immunotherapy as it improves infectivity, gene transfer, protein expression, and subsequent T-cell activation in DCs compared to wild-type HAdV5 viruses.

Heterogeneity of porcine bone marrow-derived dendritic cells induced by GM-CSF

“…The pig has been considered an important large animal model, and gnotobiotic miniature pigs are probably the best model for studying immunology [18]. The porcine immune system resembles the human immune system with respect to DC biology, because their gene expression signature for cDC2 is close to the human counterpart [14, 25, 26]. The classical protocols for generating in vitro DCs in humans and mice are similar to the porcine method.…”

A Novel Piggyback Strategy for mRNA Delivery Exploiting Adenovirus Entry Biology

“…To assess the capacity of this system to transduce multiple cell and tissue types, we utilized an adenoviral vector based on human adenovirus serotype 5 (huAd5) with fiber knob chimerism whereby the knob domain of the huAd5 is replaced with the fiber knob of porcine adenovirus serotype 4. In our earlier studies we showed that the resulting chimeric adenovirus vector (AdPK4) possesses enhanced infectivity based on gene transfer that exploits glycan binding of target cells [17]. We hypothesized that the negatively charged mRNA would associate with the positively charged polylysine in a manner similar to plasmid DNA, and that the resulting AdpL-mRNA conjugate would facilitate delivery of the mRNA in a manner comparable to what we had observed for plasmid DNA.…”

A novel single-chain antibody redirects adenovirus to IL13Rα2-expressing brain tumors

“…In order to generate a fiber shuttle vector, the pKan 566 adenoviral genome (kindly gifted from Dr. Curiel at Washington University in Saint Louis), which contains the gene of fiber fibritin, was used. The cDNA of scFv47, was inserted at the C-terminal of fiber fibritin by using a standard molecular technique, resulting in pKan-scFv47FF 21 27 45 . With this fiber shuttle vector, recombinant HAd5 backbones containing an enhanced green fluorescence protein (eGFP) under the control of the CMV promoter in the E1 deleted region (replication incompetent Ad5scFv47FF-CMV-GFP) were generated.…”