Protection conferred by a recombinant Marek’s disease virus that expresses the spike protein from infectious bronchitis virus in specific pathogen-free chicken

Abstract

BackgroundIn many countries, the predominant field isolates of infectious bronchitis virus (IBV) have been classified as QX-like strains since 1996. However, no commercial vaccines that are specific for this type of IBV are currently available. Therefore, there is an urgent need to develop novel vaccines that prevent QX-like IBV infection.ResultsA recombinant Marek’s disease virus (MDV), rMDV-S1, that expresses the S1 subunit of the spike (S) protein from the QX-like infectious bronchitis virus (IBV) was constructed by inserting the IBV S1 gene into the genome of the CVI988/Rispens strain of MDV. Specific pathogen-free (SPF) chickens that were vaccinated with rMDV-S1 were protected when challenged with the QX-like IBV. They were observed to have mild clinical signs of disease, a short virus-shedding period and low mortality. Additionally, the rMDV-S1 conferred full protection to chickens against virulent MDV, as did the CVI988/Rispens strain.ConclusionsOur results demonstrate that rMDV-S1 is an effective and promising recombinant vaccine for the prevention of QX-like IBV infection.

Development and Characterization of Neutralizing Monoclonal Antibodies Against the S1 Subunit Protein of QX-like Avian Infectious Bronchitis Virus Strain Sczy3

“…It is well known that it is very difficult to obtain the full-length S1 subunit from the purified IBV virions, and some expression systems are used to express it. (33)(34)(35) Most mouse MAbs raised from the IBV virions were mainly directed against the N protein of IBV; only a few MAbs were specific for the S1 subunit. (36) In the present report, a highly antigenic and hydrophilic region of the S1 protein pET-S1 was expressed and used to screen the hybridoma clones specific for S1 protein.…”

Recombinant Marek’s disease virus type 1 provides full protection against very virulent Marek’s and infectious bursal disease viruses in chickens

“…Moreover, the MDV vaccines can induce lifetime immunity in chickens with just one vaccination7. In the previous studies, recombinant HVT and MDV1 vaccines expressing antigen genes from several poultry viruses such as avian influenza virus720, Newcastle disease virus421, infectious bronchitis virus6 and IBDV522, have been developed. However, with the emergence of vv and vv+MDV strains, HVT could no longer provide efficient protection against high virulent MDV infection232425.…”

“…Over the last two decades, much attention has been paid to MDV-vectored vaccines4567. However, recombinant MDVs have been constructed exclusively using traditional homologous recombination24 or the bacterial artificial chromosome (BAC) system2829.…”

“…MDV has a large genome which consists of a unique long (UL) region and a unique short (US) region, both flanked with repeat sequences. The MDV genome has several regions that are nonessential for viral replication and therefore, suitable for the insertion of foreign genes, rendering the MDV1 vaccine strains a desirable live virus vector for expressing foreign genes4567.…”

Decreased neutralizing antigenicity in IBV S1 protein expressed from mammalian cells

“…epitope peptide expressed from Escherichia coli (E. coli) protected chickens against IBV infection (Yang et al, 2009a(Yang et al, , 2009b. Furthermore, viral vectored vaccines co-expressing the S1 protein and host cytokines have been reported to induce anti-S1 antibodies (Chen et al, 2010;Shi et al, 2011;Tomley et al, 1987;Wang et al, 2009;Zeshan et al, 2011;Zhang et al, 2012). However, in these reports of protection, recombinant antigen did not provide perfect protection and antibody titers were evaluated only by hemagglutination inhibition (HI) or enzyme-linked immunosorbent assay (ELISA); the respective authors did not indicate whether these antigens retained their native neutralizing antigenicity (Song et al, 1998;Yang et al, 2009aYang et al, , 2009b.…”