Expression and Immunogenicity of the Spike Glycoprotein of Porcine Respiratory Coronavirus Encoded in the E3 Region of Adenovirus

Abstract

The full length spike (S) gene of porcine respiratory coronavirus (PRCV) was inserted into the genome of human adenovirus type 5 downstream of the early transcription region 3 promoter. The recombinant virus replicated in cultures of the swine testicle ST cell line and directed the synthesis of S antigen to an amount of approximately 33 J.lg per 10 6 cells, as determined by ELISA. The antigen was cell-associated except in the late phase of the infection, when a low amount (4 J.lg per 10 6 cells) was released in the culture supernatant. The cell-associated antigen consisted of 2 polypeptides of 160 K and 175 K, respectively. The 160 K polypeptide comigrated with the authentic S' precursor from PRCV-infected cells. The 175 K polypeptide had the same mobility as the authentic mature S protein from PRCV-infected cells and from PRCV released in the supernatant. The extracellular recombinant antigen corresponded with the 175 K mature protein. Immunofluorescent staining gave evidence that some recombinant S protein was exposed on the cell surface; it also showed that the protein was recognized by conformation-specific anti-S monoclonal antibodies. Piglets, immunized oronasally with the recombinant adenovirus vector developed PRCV-neutralizing serum antibodies and were partially protected against PRCV -challenge.

Mucosal immunisation of African green monkeys ( Cercopithecus aethiops) with an attenuated parainfluenza virus expressing the SARS coronavirus spike protein for the prevention of SARS

“…Through each nostril, we administered Additionally, immunisation of experimental animals with the S protein of other coronaviruses induced virus-specific immunity and, in some cases, conferred protection against subsequent challenge. [17][18][19] We investigated the replication, immunogenicity, and protective effects of this experimental BHPIV3/SARS-S vaccine in African green monkeys (Cercopithecus aethiops).…”

Porcine Coronaviruses: Overview of the State of the Art

“…A single experimental PRCV vaccine has been described. A recombinant adenovirus expressing the PRCV spike glycoprotein has been found to be antigenic and partially protected vaccinated piglets upon PRCV challenge, nevertheless, no subsequent studies have been published using this vaccine (Callebaut and Pensaert 1995 ). No vaccines are available commercially.…”

The use of adenoviral vectors in gene therapy and vaccine approaches

“…The non-replicative Ad5 was used to carry the glycoprotein S (Spike) of porcine respiratory coronavirus (PRCV) and elicited mucosal immunity in pigs ( Callebaut et al., 1993 ). The animals produced neutralizing antibodies against PRCV ( Callebaut and Pensaert, 1995 ; Callebaut et al, 1996 ). Another adenoviral vector was constructed carrying haemagglutinin-esterase (HE) of bovine coronavirus (BCV) and tested in cotton rats; it induced systemic and mucosal immune responses after immunization ( Baca-Estrada et al, 1995 ).…”