Correlation of Enzyme-Linked Immunosorbent Assay Titers with Protection against Infectious Bursal Disease Virus

Infectious bursal disease virus is the causative agent of Gumboro disease, a severe infection that affects young chickens and is associated with lymphoid depletion in the bursa of Fabricius. Traditional containment strategies are based either on inactivated or live-attenuated vaccines. These approaches have several limitations such as residual virulence or low efficacy in the presence of maternally derived antibodies (MDA) but, most importantly, the impossibility to detect the occurrence of natural infections in vaccinated flocks. Therefore, the development of novel vaccination strategies allowing the differentiation of infected from vaccinated animals (DIVA) is a priority. Recently, commercial vectored and experimental subunit vaccines based on VP2 have been proved effective in protecting from clinical disease and posed the basis for the development of novel DIVA strategies. In this study, an engineered version of the VP3 protein of IBDV (His-VP3) was produced in plants, successfully purified from Nicotiana benthamiana leaves, and used to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-VP3 antibodies. The His-VP3 ELISA was validated with a panel of 180 reference sera and demonstrated to have 100% sensitivity (95% CI: 94.7–100.0) and 94.17% specificity (95% CI: 88.4–97.6). To evaluate the application of His-VP3 ELISA as a DIVA test, the novel assay was used to monitor, in combination with a commercial kit, detecting anti-VP2 antibodies, the immune response of chickens previously immunized with an inactivated IBDV vaccine, a recombinant Turkey herpes virus carrying the VP2 of IBDV (HVT-ND-IBD) or with plant-produced VP2 particles. The combined tests correctly identified the immune status of the vaccinated specific pathogen free white-leghorn chickens. Moreover, the His-VP3 ELISA correctly detected MDA against VP3 in commercial broiler chicks and showed that antibody titers fade with time, consistent with the natural decrease of maternally derived immunity. Finally, the novel assay, in combination with a VP2-specific ELISA, demonstrated its potential application as a DIVA test in chickens inoculated with VP2-based vaccines, being able to detect the seroconversion after challenge with a very virulent IBDV strain.

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Antigenic Properties and Diagnostic Potential of Baculovirus-Expressed Infectious Bursal Disease Virus Proteins VPX and VP3

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.7.4.645-651.2000 ◽

2000 ◽

Vol 7 (4) ◽

pp. 645-651 ◽

Cited By ~ 22

Author(s):

Jorge L. Martínez-Torrecuadrada ◽

Beatriz Lázaro ◽

José F. Rodriguez ◽

J. Ignacio Casal

Keyword(s):

Disease Virus ◽

Infectious Bursal Disease Virus ◽

Neutralizing Antibodies ◽

Insect Cells ◽

Indirect Elisa ◽

Infectious Bursal Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Diagnostic Potential ◽

Antigenic Properties ◽

Bursal Disease

ABSTRACT The routine technique for detecting antibodies specific to infectious bursal disease virus (IBDV) is a serological evaluation by enzyme-linked immunosorbent assay (ELISA) with preparations of whole virions as the antigens. To avoid using complete virus in the standard technique, we have developed two new antigens through the expression of the VPX and VP3 genes in insect cells. VPX and especially VP3 were expressed at high levels in insect cells and simple to purify. The immunogenicity of both proteins was similar to that of the native virus. VPX was able to elicit neutralizing antibodies but VP3 was not. Purified VPX and VP3 were tested in an indirect ELISA with more than 300 chicken sera. There was an excellent correlation between the results of the ELISA using VPX and those of the two commercial kits. VP3 did not perform as well as VPX, and the linear correlation was significantly lower. A comparison with the standard reference technique, seroneutralization, showed that the indirect ELISA was more sensitive. Therefore, VPX-based ELISA is a good alternative to conventional ELISAs that use whole virions.

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Diagnostic potential of recombinant protein of hexahistidine tag and infectious bursal disease virus VPX expressed in Escherichia coli

Acta Veterinaria Hungarica ◽

10.1556/avet.55.2007.3.14 ◽

2007 ◽

Vol 55 (3) ◽

pp. 405-415 ◽

Cited By ~ 1

Author(s):

S. Hosseini ◽

A. Omar ◽

I. Aini ◽

A. Ali

Keyword(s):

Recombinant Protein ◽

Disease Virus ◽

Infectious Bursal Disease Virus ◽

Current Method ◽

Infectious Bursal Disease ◽

Enzyme Linked Immunosorbent Assay ◽

E Coli ◽

Hexahistidine Tag ◽

Diagnostic Potential ◽

Bursal Disease

The current method to detect antibody titre against infectious bursal disease virus (IBDV) in chickens is based on enzyme-linked immunosorbent assay (ELISA) using whole virus as coating antigen. Coating the ELISA plates requires a purified or at least semi-purified preparation of virus as antigen, which needs special skills and techniques. In this study, instead of using whole virus, recombinant protein of hexahistidine tag (His 6 tag) and VPX protein of IBDV expressed in E. coli was used as an alternative antigen to coat the ELISA plates. There was a good correlation coefficient (R 2 = 0.972) between the results of the ELISA using plates coated with monoclonal antibody against His 6 tag and those of the commercial IBDV ELISA kit. Hence, His 6 tag and VPX recombinant protein expressed in E. coli has the potential for the development of ELISA for the measurement of IBDV-specific antibody.

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