Evaluation of innate immunity and vector toxicity following inoculation of bovine, porcine or human adenoviral vectors in a mouse model

Abstract

Nonhuman adenovirus (Ad) vectors derived from bovine Ad serotype 3 (BAd3) or porcine Ad serotype 3 (PAd3) can circumvent pre-existing immunity against human Ad (HAd). We have previously reported differential transduction of human and nonhuman cells by these Ad vectors, and their distinct receptor usage and biodistribution. To compare the induction of innate immunity, vector toxicity and vector uptake by Kupffer cells (KCs) following intravenous administration of PAd3, BAd3, or HAd5 vectors in mice, we determined mRNA expression levels of proinflammatory chemokines and cytokines, and Toll-like receptors (TLRs) in the liver and spleen. Tissue toxicity of these vectors was assessed by comparing serum levels of liver-specific enzymes, histopathology and Kupffer cell (KC) depletion. Compared to the HAd5 vector, PAd3 and BAd3 vectors were more potent stimulators of innate immune responses as indicated by enhanced mRNA expression of TLRs and proinflammatory chemokines and cytokine genes. Histopathological changes in the liver were most pronounced in HAd5-inoculated mice while BAd3-or PAd3-inoculated mice revealed mild histologic changes that were confined to early time points. Inoculation with HAd5 or PAd3 vectors resulted in a significant (P <0.05) decline of the number of KCs in the liver. Together, these results extend our previous observations regarding distinct in vivo biology of nonhuman and human Ad vectors.

Vaccination with Adenovirus Serotypes 35, 26, and 48 Elicits Higher Levels of Innate Cytokine Responses than Adenovirus Serotype 5 in Rhesus Monkeys

“…Vectors constructed using these viruses have been shown to differ significantly in terms of primary receptor usage (1,9,13,40,50), intracellular trafficking patterns (14,22,31,32), transduction and activation of dendritic cells (2,11,20,29,36,53), utilization of secondary receptors (15,48), cellular tropism (3,16,33,44,46,47), and interaction with pattern recognition receptors (PRR) (12,18,35). The species C adenovirus serotype 5 (Ad5), the species B2 adenovirus serotype 35 (Ad35), and the species D adenovirus serotype 26 (Ad26) are currently being evaluated as vaccine candidates in clinical trials, yet relatively little is known about the possible differences in innate immunity induced by these vectors.…”

Sequential administration of bovine and human adenovirus vectors to overcome vector immunity in an immunocompetent mouse model of breast cancer

“…or systemic (i.v.) (Sharma et al, 2010a) inoculations of BAd-GFP presumably reflect a complex relationship between innate immunity and the route/dose of vector administration. The differences in lymphoid cell population associated with these two routes determine the potency and quality of innate and adaptive immune responses (Zinkernagel, 2000).…”

“…For repeat vector inoculations, RNA expression was quantified and calibrated with respect to the residual gene expression (from the first inoculation) present in the Day 0.25 PBS-inoculated control samples of the repeat inoculation groups. The gene expression pattern of chemokines, CCL1–5, CXCL10, CXCL11, Toll-like receptors (TLR) 1–9, TICAM, and MyD88 as indicators of an innate immune response, were determined from tumor and spleen RNA samples collected at Day 0.25 and quantified as previously described (Sharma et al, 2010a). The gene expression levels of each chemokine or TLR molecule from HAd-GFP- or BAd-GFP-treated mice was calibrated with respect to the control levels (as 100%) in the PBS-inoculated mice.…”

“…Blood samples collected at Days 0.25, 1 and 2 post-vector inoculations were used to monitor the levels of hepatic enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) with previously described method (Sharma et al, 2010a). …”

“…The immunohistochemical analysis was performed for GFP expression in tumor tissues using a mouse anti-GFP antibody ( Millipore Corporation , Billerica, CA, USA). The analysis for Kupffer cells in the liver tissues was done using a mouse anti-F4/80 antibody ( Abcam , Cambridge, MA, USA) (Sharma et al, 2010a). …”