title: Defining a Novel Role for the Coxsackievirus and Adenovirus Receptor in Human Adenovirus Serotype 5 TransductionIn Vitroin the Presence of Mouse Serum.
abstract: Human adenoviral serotype 5 (HAdV-5) vectors have predominantly hepatic tropism when delivered intravascularly, resulting in immune activation and toxicity. Coagulation factor X (FX) binding to HAdV-5 mediates liver transduction and provides protection from virion neutralization in mice. FX is dispensable for liver transduction in mice lacking IgM antibodies or complement, suggesting that alternative transduction pathways exist. To identify novel factor(s) mediating HAdV-5 FX-independent entry, we investigated HAdV-5 transductionin vitroin the presence of serum from immunocompetent C57BL/6 or immunocompromised mice lacking IgM antibodies (Rag 2-/-and NOD-scid-gamma [NSG]). Sera from all three mouse strains enhanced HAdV-5 transduction of A549 cells. While inhibition of HAdV-5-FX interaction with FX-binding protein (X-bp) inhibited transduction in the presence of C57BL/6 serum, it had negligible effect on the enhanced transduction observed in the presence of Rag 2-/-or NSG serum. Rag 2-/-serum also enhanced transduction of the FX binding-deficient HAdV-5HVR5*HVR7*E451Q (AdT*). Interestingly, Rag 2-/-serum enhanced HAdV-5 transduction in a FX-independent manner in CHO-CAR and SKOV3-CAR cells (CHO or SKOV3 cells transfected to stably express human coxsackievirus and adenovirus receptor [CAR]). Additionally, blockade of CAR with soluble HAdV-5 fiber knob inhibited mouse serum-enhanced transduction in A549 cells, suggesting a potential role for CAR. Transduction of HAdV-5 KO1 and HAdV-5/F35 (CAR binding deficient) in the presence of Rag 2-/-serum was equivalent to that of HAdV-5, indicating that direct interaction between HAdV-5 and CAR is not required. These data suggest that FX may protect HAdV-5 from neutralization but has minimal contribution to HAdV-5 transduction in the presence of immunocompromised mouse serum. Alternatively, transduction occurs via an unidentified mouse serum protein capable of bridging HAdV-5 to CAR.IMPORTANCEThe intravascular administration of HAdV-5 vectors can result in acute liver toxicity, transaminitis, thrombocytopenia, and injury to the vascular endothelium, illustrating challenges yet to overcome for HAdV-5-mediated systemic gene therapy. The finding that CAR and potentially an unidentified factor present in mouse serum might be important mediators of HAdV-5 transduction highlights that a better understanding of the complex biology defining the interplay between adenovirus immune recognition and cellular uptake mechanisms is still required. These findings are important to inform future optimization and development of HAdV-5-based adenoviral vectors for gene therapy.
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Estrella
authors.initials: E
authors.lastname: Lopez-Gordo
authors.affiliation: Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Andor
authors.initials: A
authors.lastname: Doszpoly
authors.affiliation: Department of Oncology, University of Oxford, Oxford, United Kingdom.
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Duffy
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Lynda
authors.initials: L
authors.lastname: Coughlan
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Angela C
authors.initials: AC
authors.lastname: Bradshaw
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Katie M
authors.initials: KM
authors.lastname: White
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Laura
authors.initials: L
authors.lastname: Denby
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Nicklin
authors.affiliation: Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom Andy.Baker@ed.ac.uk.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Baker
mesh_terms: D000072283:A549 Cells; D000260:Adenoviruses, Human / Q000145:classification / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein / Q000378:metabolism*; D005170:Factor X / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D007121:Immunocompetence; D016867:Immunocompromised Host; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D011485:Protein Binding; D065288:Serogroup; D044967:Serum / Q000276:immunology*; D056189:Viral Tropism
chemical_list: C568772:CLMP protein, mouse; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D005170:Factor X
keywords: CAR; adenovirus; receptor; serum; tropism