Taxonomic studies on strains of avian infectious bronchitis virus using neutralisation tests in tracheal organ cultures

Abstract

The antigenic relationships of 24 strains of avian infectious bronchitis virus (IBV) were investigated by serum neutralisation tests performed in chick embryo tracheal organ cultures. The serum dilution that neutralised 100 median ciliostatic doses (CD50) of virus was estimated from the linear relationship between varying concentrations of each virus strain and the neutralisation titre of homologous antiserum; this dilution defined 1 antibody unit. Antisera diluted to contain 20 antibody units were then tested by neutralisation against 1.5--2.5 log10 CD50 of each strain. Clusters of both strains and antisera in turn were established by methods of numerical taxonomy using as measures of resemblance Euclidean distance and correlation coefficient, and by analysis by principal components. These analyses identified a group of 8 similar strains; neutralisation of the remaining 16 strains was slight. Similar results were obtained by classifying antisera, except that a further group of 3 antisera was demonstrated, each having a neutralising capacity for most strains. Implications for vaccine formulation are discussed.

Detection of infectious bronchitis virus

“…Traditionally, strain classification into serotypes has been by VNTs performed in various systems, including embryonated eggs (Dawson & Gough, 1971;Cunningham, 1973;Cowen & Hitchner, 1975;Lohr, 1976Lohr, , 1977Gelb et al, 1981Gelb et al, , 1989Gelb et al, , 1991Davelaar et al, 1984;Picault et al, 1986;Karaca et al, 1990;Cubillos et al, 1991;Capua et al, 1998), cell culture (Hopkins, 1974;Cowen & Hitchner, 1975;Wadey & Faragher, 1981;Csermelyi et al, 1988), or TOCs (Johnson & Marquardt, 1975;Darbyshire et al, 1979;Cook, 1984;Cook et al, 1987Cook et al, , 1999Hinze et al, 1991;Ignjatovic & McWaters, 1991;Cubillos et al, 1991;Parsons et al, 1992;Dhinakar Raj & Jones, 1996b;Ignjatovic & Ashton, 1996;Wang et al, 1997). There are several reports on serotyping by the HI test (Lashgari & Newman, 1984;Brown & Bracewell, 1985;Toro et al, 1987;Cook et al, 1987;Capua et al, 1998Capua et al, , 1999.…”

The Protective Immune Response against Infectious Bronchitis Virus Induced by Multi-Epitope Based Peptide Vaccines

“…A standard neutralizing antibody test was performed using chick embryo tracheal organ cultures. 24) Doubling dilutions of chicken anti-peptide vaccines sera were incubated with equal volumes of a single concentration of IBV strain SAIBk (100 ciliostatic doses) for 30 min at room temperature. Residual infectivity was assayed in tracheal organ cultures (five tubes per dilution).…”

Demonstration of antibodies to Turkey rhinotracheitis virus in serum from commercially reared flocks of chickens

“…These were carried out in chick embryo trachéal organ cultures as described previously (Darbyshire et al, 1979) using log 10 2.0 median ciliostatic doses of TRT virus strain 3B. Four pools of serum, each from five chickens, were made from each flock.…”