Comparison of the enzyme‐linked immunosorbent assay (elisa), haemagglutination inhibition test and agar gel precipitation test for detection of antibodies to avian infectious bronchitis virus

Abstract

The immune response after vaccination with infectious bronchitis virus (IBV) under field conditions was measured by the ELISA, haemagglutination-inhibition (HI) and agar-gel precipitin (AGP), tests. Vaccinations were performed in three flocks and one experimental group via the drinking water with the vaccine strains H 120 and H 52. In each flock 40 random serum samples were taken every 2 weeks and tested individually. In the experimental group blood samples were collected every week from each of the 10 chickens. The primary vaccination with H 120 resulted in a rapid increase of antibody titre as detected by ELISA followed by a slow decrease over the next few weeks. By the HI and AGP tests no antibody responses could be seen after this primary vaccination. Revaccination with the H 52 strain provoked a further increase in ELISA titres. In the experimental group, and in flock W, a similar increase occurred by the HI test and precipitating antibodies appeared. The formation of HI antibodies in flock T (nipple waterers) was somewhat retarded and precipitating antibodies were just detectable. In flock F revaccination did not result in the immediate production of HI and AGP antibodies. However, 6 weeks after revaccination a significant rise in ELISA, HI and AGP antibodies was observed, probably as the result of a field infection. It was demonstrated that, based on the higher sensitivity, the ELISA test is more suitable than HI and AGP to monitor antibody responses to vaccination against infectious bronchitis. Strain specificity in the HI test is discussed as a reason for its failure to detect antibodies after primary vaccination with the highly attenuated vaccine strain H 120.

Detection of infectious bronchitis virus

“…Reports of indirect ELISAs show them to be group specific (Garcia & Bankowski, 1981;Marquardt et al, 1981;Zellen & Thorsen, 1987;Perrotta et al, 1988;Karaca et al, 1990;De Wit et al, 1997). Antibodies can first be detected by ELISA within 1 week after vaccination or infection (Marquardt et al, 1981;Mockett & Darbyshire, 1981;Hawkes et al, 1983;Monreal et al, 1985;De Wit et al, 1997, 1998a. This early detection does not automatically lead to a high sensitivit y.…”

“…The reverse was also true. Monreal et al (1985), Box et al (1988) andDe Wit et al (1997) also reported that the HI test using M41 antigen was not able to detect a primary H120 vaccination, but none of these reports consider whether using Holland antigen would improve detection. This demonstrates that virus strain selection for IBV HI antigen production is important, for sensitivity of the test as well as for interpretation of the results.…”

“…The sensitivity was 100 and 55% after H52 infection of non-vaccinated and vaccinated 11-week-old SPF chickens, respectively. Monreal et al (1985) reported that H120 vaccination of young layers via drinking water did not induce an immune response detectable by AGPT, in contrast to vaccination of 10-week-old layers, housed in an isolator, with H52, where the AGPT showed a sensitivity of 90%. The same H52 vaccination applied through the drinking water under field conditions resulted in a lower and delayed humoral response.…”

“…This is because precipitating antibodies do not occur regularly and are transient in appearance (Witter, 1962;Wilcox et al, 1983;Monreal et al, 1985;De Wit et al, 1992. Precipitins are usually detected about 1 week p.i., generally followed by a rapid decrease in percentage of positive samples a few weeks later (Witter, 1962;Gazdzinski et al, 1977;De Wit et al, 1997), although extended periods have been reported (Witter, 1962;Gazdzinski et al, 1977;MacDonald et al, 1983;Monreal et al, 1985). The sensitivity of the AGPT varies from 0 to 100%, depending on the IBV strain inoculated, application route, age at infection, presence of MDA or vaccinal immunity at the time of challenge and test performance.…”

“…Due to the many variations in experimental conditions, test performance and type of antibodies that are detected by the different tests, many different results are reported. However, generally, antibodies can first be detected by ELISA, followed by AGPT and HI test, and last by VNT (Marquardt et al, 1981;Mockett & Darbyshire, 1981;Hawkes et al, 1983;Monreal et al, 1985;De Wit et al, 1997, 1998a.…”