Construction and Characterization of a Novel Recombinant Attenuated and Replication-Deficient Candidate Human Adenovirus Type 3 Vaccine: “Adenovirus Vaccine Within an Adenovirus Vector”

Abstract

Human adenoviruses (HAdVs) are highly contagious and result in large number of acute respiratory disease (ARD) cases with severe morbidity and mortality. Human adenovirus type 3 (HAdV-3) is the most common type that causes ARD outbreaks in Asia, Europe, and the Americas. However, there is currently no vaccine approved for its general use. The hexon protein contains the main neutralizing epitopes, provoking strong and lasting immunogenicity. In this study, a novel recombinant and attenuated adenovirus vaccine candidate against HAdV-3 was constructed based on a commercially-available replication-defective HAdV-5 gene therapy and vaccine vector. The entire HAdV-3 hexon gene was integrated into the E1 region of the vector by homologous recombination using a bacterial system. The resultant recombinants expressing the HAdV-3 hexon protein were rescued in AD293 cells, identified and characterized by RT-PCR, Western blots, indirect immunofluorescence, and electron microscopy. This potential vaccine candidate had a similar replicative efficacy as the wild-type HAdV-3 strain. However, and importantly, the vaccine strain had been rendered replication-defective and was incapable of replication in A549 cells after more than twentygeneration passages in AD293 cells. This represents a significant safety feature. The mice immunized both intranasally and intramuscularly by this vaccine candidate raised significant neutralizing antibodies against HAdV-3. Therefore, this recombinant, attenuated, and safe adenovirus vaccine is a promising HAdV-3 vaccine candidate. The strategy of using a clinically approved and replication-defective HAdV-5 vector provides a novel approach to develop universal adenovirus vaccine candidates against all the other types of adenoviruses causing ARDs and perhaps other adenovirus-associated diseases. Keywords Adenovirus vaccine Á Human adenovirus type 3 (HAdV-3) Á Replication-deficient adenovirus vector Á Immunity in BALB/c mice Á Recombination Yuqian Yan and Shuping Jing have contributed equally to this work.

Development and Application of a Fast Method to Acquire the Accurate Whole-Genome Sequences of Human Adenoviruses

“…Prior to sequencing, we performed restriction endonuclease analysis (REA) to check and identify the genomic DNA rapidly. EcoRI was used, and an in silico REA map was generated first by the Vector NTI 11.5.1 software (Invitrogen Corp., San Diego, CA, United States) (Zhao et al, 2014;Yu et al, 2016;Zhang et al, 2017;Yan et al, 2020a). Then, the genomic DNA was digested by EcoRI according to the instruction.…”

Molecular Typing and Rapid Identification of Human Adenoviruses Associated With Respiratory Diseases Using Universal PCR and Sequencing Primers for the Three Major Capsid Genes: Penton Base, Hexon, and Fiber

“…HAdV types C1 to B7 account for more than 80% of the HAdV infections in infants and children ( Piedra et al, 1998 ). Globally, HAdV-B3 is among the most common types implicated in HAdV respiratory infections in children and adults ( Schmitz et al, 1983 ; Gray et al, 2007 ; Chang et al, 2008 ; Yan et al, 2021 ). In South America, HAdV-B7 has been a predominant strain associated with RTIs requiring hospitalization in many countries ( Li et al, 1996 ; Carballal et al, 2001 ).…”

“…In South America, HAdV-B7 has been a predominant strain associated with RTIs requiring hospitalization in many countries ( Li et al, 1996 ; Carballal et al, 2001 ). In Asia, HAdV-B3 and -B7 have been the predominant types associated with RTIs in children ( Li et al, 1996 ; Lin et al, 2004 ; Chang et al, 2008 ; Tsou et al, 2012 ; Han et al, 2013 ; Zhao et al, 2014 ; Chen et al, 2016 ; Wang et al, 2016 ; Yu et al, 2016 ; Yan et al, 2021 ), while HAdV-B7 are associated with higher severity of illness and fatality rate ( Zhao et al, 2014 ; Chen et al, 2016 ; Yu et al, 2016 ). In Europe, HAdV-B3 and HAdV-B7 are highly virulent and potentially deadly types, especially for children ( Lion, 2014 ).…”

The use of adenoviral vectors in gene therapy and vaccine approaches

“…The adenoviral hexon protein is a major component that drives the host immune response. Replacing the hexon of Ad5 with the one from Ad3 reduced neutralization of viral particles ( Yan et al, 2021 ). As well exchange of the hexon gene of Ad3 with the hexon from Ad14 generated a chimeric vector that was not neutralized by antibodies against Ad3 ( Su et al, 2016 ).…”