Antibody fragments, expressed by a fowl adenovirus vector, are able to neutralize infectious bursal disease virus

Abstract

Single-chain variable fragments (scFv) contain the heavy and light chain variable domains of immunoglobulin, joined by a short peptide linker. Previously, our laboratory has produced neutralizing scFv to epitopes of infectious bursal disease virus (IBDV). The in vitro delivery and expression of one of these scFv with and without the C H 2-C H 4 Fc domain of chicken IgY attached (scFv-Fc) by a serotype 8 fowl adenovirus (FAdV-8) vector was investigated in the present study. A panel of FAdV-8 vectors was constructed, each containing a different transgene (scFv or scFv-Fc), a different promoter to drive scFv and scFv-Fc transcription (CMVie or the fowl adenovirus major late promoter), and a different sized, right-hand end genomic deletion (52 bp or 2.3 kb). This panel was used to establish what effect these variables had on protein production, viral replication and scFv transcription, as measured by enzyme-linked imunosorbent assay and real-time polymerase chain reaction. Our results showed that, using a FAdV-8 vector containing the optimal CMVie promoter/2.3 kb deletion combination, we successfully expressed a secreted form of both scFv and scFv-Fc that were able to neutralize IBDV both in vitro and in ovo. These studies indicate that the FAdV-8 vector may be a promising candidate to deliver and express therapeutic molecules such as scFv and scFv-Fc in vivo in poultry.

Recombinant Antibodies in Veterinary Medicine: An Update

“…A scFv anti-infectious bronchitis virus (IBV) showed neutralizing activity ( 45 ); similarly, a scFv-Fc and scFv anti-infectious bursal disease virus (IBDV) reduced viral titers in vivo and in ovo ( 46 , 47 ). NDV is a highly contagious viral infection that affects poultry and domestic birds.…”

Development of Novel Adenoviral Vectors to Overcome Challenges Observed With HAdV-5–based Constructs

“…For instance, bovine AdV-3 (BAdV-3), porcine AdV-3 (PAdV-3) and -5, canine AdV-2 (CAdV-2), fowl AdV-1 (FAdV-1), -8, -9, and -10 have been modified to respectively express homologous host-relevant antigens in an attempt to build affordable and effective vaccines. 143 , 144 , 145 , 146 , 147 , 148 In spite of this research effort, none of these approaches have led to the market introduction of any recombinant AdV-based veterinary vaccines. Currently, the only promising such vaccine candidate is a replication-deficient HAdV-5 vector expressing the relevant genes of the foot and mouth disease virus.…”

“… 182 Four FAdV serotypes have been vectorized and successfully propagated in avian cells: FAdV-1, -8, -9, and -10. 148 , 183 , 184 , 185 FAdV-1 (CELO, Chicken Embryo Lethal Orphan) and FAdV-9 (FAdV-D) have been further studied as they abortively infect human cells while yielding high transgene expression unaffected by PEI. 183 , 186 Based on these findings, CELO vectors have been constructed to express IL-2, HSV-1 tyrosine kinase, or p53 and have demonstrated long-term gene expression in preclinical models.…”

Intranasal Immunization with a Recombinant Avian Paramyxovirus Serotypes 2 Vector-Based Vaccine Induces Protection against H9N2 Avian Influenza in Chicken

“…The vector vaccine expressing HA protein of H9N2 virus is an ideal substitute for inactivated vaccine [ 18 , 19 ]. There are some viral vectors commonly used to construct live vaccines of avian recombinant viruses, such as fowl pox virus [ 20 ], Newcastle disease virus [ 21 ], adenovirus [ 22 ], Marek’s disease virus [ 23 ], and Herpesvirus of Turkeys [ 24 ]. The NDV vector vaccine expressing HA protein could be administered by drinking water, and induce mucosal antibody and cellular immunity [ 25 ], which can protect poultry from AIV infection [ 26 ].…”