Recombinant nucleocapsid protein is potentially an inexpensive, effective serodiagnostic reagent for infectious bronchitis virus

Abstract

The nucleocapsid protein of the Gray strain of infectious bronchitis virus (IBV) is highly immunogenic and cross-reactive among various distinct serotypes. Recombinant nucleocapsid polypeptide expressed in bacteria with a histidine tag at the amino terminus has been used as antigen for developing an assay to detect IBV-specific antibody. This fusion protein was produced readily in bacteria and easily purified with a nickel column which bound to the histidine tag. Conditions were optimized for using these preparations for an IBV-specific ELISA. Although differences in optical densities could be detected between pre-immune and positive sera for the Ark, Mass, and Gray strains with antigen concentrations between 50 and 0.1 microg per well, the greatest differences could be detected with 3 and 1.5 microg of protein per well. Maximum differences in optical densities between pre-immune and positive sera were obtained using 2.4 microg per well of protein and sera diluted between 1:80 and 1:160. In addition, as little as 30 ng/dot of recombinant nucleocapsid consistently detected IBV-specific sera in immunoblot assays which have convenient field applications.

Serodiagnosis Using Recombinant Nipah Virus Nucleocapsid Protein Expressed in Escherichia coli

“…The production of recombinant proteins in E. coli as capturing antigens for the diagnosis of diseases has been widely used for virological studies (12,14). Expression of recombinant protein in E. coli, however, always produces inactive aggregates (inclusion bodies) in the host cell instead of forming its native, soluble, and biologically active conformation.…”

Detection of Specific Antibodies to Severe Acute Respiratory Syndrome (SARS) Coronavirus Nucleocapsid Protein for Serodiagnosis of SARS Coronavirus Pneumonia

“…Previous studies with animal coronaviruses (5,17). In one study, recombinant nucleocapsid protein expressed in Escherichia coli with a histidine tag at the amino terminus, the fusion protein purified with a nickel column, was used as the antigen for development of an assay to detect infectious bronchitis virus-specific antibody (11). Recently, Shi et al described the use of an antigen-capture ELISA for detection of SARSCoV nucleocapsid protein antibodies.…”

Construção de uma biblioteca de fragmentos de anticorpos monoclonais de galinhas com cadeia única (scFv) por phage display com reatividade cruzada para estirpes heterólogas do vírus da bronquite infecciosa aviária

“…Portanto, a utilização de anticorpos monoclonais contra essa proteína viral é de grande valor para a detecção direta do VBI em amostras teciduais suspeitas de infecção, por meio de técnicas de imunofluorescência, imunoperoxidase ou de ELISA (DE WIT, 2000;NDIFUNA, et al, 1998).…”