Breadth of protection of the respiratory tract provided by different live-attenuated infectious bronchitis vaccines against challenge with infectious bronchitis viruses of heterologous serotypes

Abstract

The regime of administering the infectious bronchitis (IB) Ma5 vaccine (Massachusetts serotype) at 1 day old and the heterologous 4/91 vaccine at 2 weeks of age, was shown to be highly effective in protecting the respiratory tract of speci® ed pathogen free chickens. Protection, as measured by assessing ciliary activity of the tracheal epithelium following challenge, was excellent against challenge at 5 weeks of age with IB strains of many serotypes, isolated from disease outbreaks in different parts of the world. This vaccination protocol was more effective than revaccination with a vaccine of the same serotype as the ® rst vaccine. Furthermore, signi® cantly better protection was seen when the Ma5 vaccine was given before, rather than at the same time as or following, the 4/91 vaccine.It is suggested that the use of these two IB vaccines will frequently broaden the protection possible against challenge with IB isolates of many different serotypes, without the need to develop a new IB vaccine to combat each new IB serotype that emerges.

Detection of infectious bronchitis virus

“…Another important factor that influences the degree of humoral response after an infection or vaccination is the immunity derived from previous vaccination or infection (Gazdzinski et al, 1977;Macdonald et al, 1981;, 1985Pensaert & Lambrechts, 1994;De Wit et al, 1997, Cook et al, 1999. As a result, the sensitivity of antibody detecting tests can be much lower in vaccinated chickens compared with unvaccinated chickens.…”

“…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.…”

“…A CIS is labour intensive, expensive, and requires many animals and isolation facilities (Raggi & Lee, 1957, 1965Hofstad, 1961Hofstad, , 1981Winterfield & Hitchner, 1962;Hitchner et al, 1964;Cowen et al, 1971;Rosenberger et al, 1976;Lohr, 1977;Darbyshire, 1980Darbyshire, , 1985Gelb et al, 1981Gelb et al, , 1991Lambrechts et al, 1993;Cook et al, 1998Cook et al, , 1999. Hinze et al (1991) and Dhinakar Raj & Jones (1996b) used a more economical in vitro alternative for the CIS: the cross-immunization test (CIT).…”

Infectious bronchitis virus S1 gene sequence comparison is a better predictor of challenge of immunity in chickens than serotyping by virus neutralization

“…As valuable as the findings of these assays are, however, the major goal is to establish the relationship of field strains to vaccine strains using cross-challenge studies in the chicken (Cook et al ., 1999). Vaccines are the primary method of controlling IBV infections in commercial chickens.…”

Serological Studies of Infectious Bronchitis Vaccines against Japanese Field Isolates of Homologous and Heterologous Genotypes

“…A VN test with immune sera would be required to confirm the efficacy of vaccines, especially in heterologous genotypes. Immunization with two kinds of vaccine strains could provided cross-protection against challenge with IBV field strains [5]. Therefore, combination of plural vaccines could yield improved performance to induce heterologous crossprotection.…”