JPH0413997B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a poultry infectious bronchitis (abbreviated as IB) virus strain. The application of live infectious bronchitis vaccines to poultry has been known for many years. Infectious bronchitis is a serious disease of the respiratory system, kidneys, and fallopian tubes in poultry. The cause of this syndrome is a coronavirus. Poultry is severely affected by this livestock epidemic. Infectious bronchitis continues to cause high mortality, especially among young poultry. In addition to mortality, there are also more or less severe symptoms to the trachea and damage to the ovipositor canal, resulting in a decrease in egg production due to IB infection. Furthermore, IB virus infection promotes latent viral or bacterial infections, thus causing economic damage, especially in the broiler industry. Vaccines derived from inactivated viruses as well as from live viruses are applied in the fight against infectious bronchitis. However, it has been found that after inactivation of the viruses, for example by formalin and ultraviolet light, a loss of immunogenic properties occurs [MSHofstad, Diseases of Poultry].
Biester and Schwarte, lowa State University
Press Ames. (1965), 615]. Healthy chickens can also be killed or become infected by primary vaccination using live non-attenuated or poorly attenuated virus vaccines, which can cause 2- to 3-week-old animals or Since it poses a particular danger to hens just before egg-laying or during egg-laying, those skilled in the art choose to use killed vaccines or live vaccines, thereby increasing the harmlessness of the vaccine. I tried. The vaccine is based on an attenuated original infectious bronchitis virus isolate. For example, the H strain is currently in widespread use on a worldwide scale, as it has a broad spectrum of immunity, especially against the Masachi and Connecticut viruses and IB-viruses, and the H strain has been isolated by Bijlenga et al. It is disclosed in the literature that it is isolated and attenuated [Tijdschr. Diergeneesk. 81:43, “
Infectious bronchitis in chicks in the
Netheriands″ (1956), Tijdschr.Diergeneesk.
85:230 (1960), Tijdschr.Diergeneesk.85:279
(1960) and Tijdschr.Diergeneesk.85:398
(1960). In order to obtain these improved vaccines, viruses that have undergone embryonic passage 25 or more times to reduce their pathogenicity and transmissibility are used, such as the Masachi Yusetsu type, more specifically IBVW48, M41. ,
82828 has been used to date in addition to those H52 and H120 strains. Both H52 and H120 strains were obtained by passing approximately 52 and 120 passages, respectively, on embryonic chicken eggs, and connecticut isolates such as
A5968 or Beaudette type IBV (IBV-
42). The immunizing potential of these viruses is highly specific for the Masachi-Yusetsu or Connecticut types of IB viruses. Although the use of these modified strain(s) vaccines currently appears to be safe and effective, these vaccines are not available in the literature [Avian
diseases vol.20, No.1, p.42 and 177 and
Avian Diseases vol.19, No.2, p.323and 583]
As appeared in 2007, it is still not possible to completely satisfactorily prevent the outbreak of infectious bronchitis under certain conditions. The shortcomings of current IB vaccines are attributed to the significant degree of antigenic variation of the virus (e.g.
Archivfuer die Gesamte Virusforschung 34,
p.32 (1971) and Cunningham CH, Develop.
See Bioold Standard, 33, 311 (1976)]. Efforts have therefore been made to achieve satisfactory vaccination of poultry by producing and applying combinations of vaccines derived from several IBV strains of different serotypes. However, clear difficulties have been encountered in reducing the immunogenic properties of the respective starting viruses, resulting from interactions. [Am.J.Vet.Res.36,
4, 524 and 525 (1965) and Avian Diseases
12, 577 (1968)]. Therefore, IB with sufficient immunogenic properties
There remains a huge demand for vaccines. It is recognized that continued improvement of the vaccines is still significantly hampered by changes in the immunogenic and other properties of the current IB viruses after multiple passages in embryonic chicken eggs. Good morning. It is hoped that a new serotype vaccine will emerge.
It has been pointed out that there is a lack of serological immunological test methods that can be used sufficiently effectively [Avian Diseases,
19, 2, 323 and 324 (1975)]. As a result of extensive research and numerous experiments, many new
It was surprising that the IB virus was obtained. These IB viruses are described, for example, in the literature [American
Association of Pathologists, “Isolation and
Identification of Avian Pathogens″, Page
184 (1975)] from the IB viruses of type H (e.g. IBH120 and IBH52), which are currently most frequently used, as found in cross neutralization tests (virus neutralization tests) according to the method described in It can be seen that it is biased.
That is, this bias is observed in challenge tests using antiserum diluted in a 1:5 ratio and in subsequent virus reisolation tests. In other words, H
Upon inoculation with this type of virus, the inoculated animal exhibits virus replication in the mucous membranes of the respiratory system after challenge with the novel polarized IB virus.
It lacks protection against. Humoral antibodies directed against IBH strains also fail to neutralize significant amounts of IB virus of the biased forms described above. What is particularly important in actual operations is that the new IB virus causes respiratory symptoms in animals that exhibit high antibody titers against the IBH strain, and also causes these symptoms in poultry during egg production, resulting in a decrease in egg production. That's true. Examples of these new viruses are those defined by the Dutch National Symbols Act, namely Utrecht.101,
(U.101), Utrecht.102 (U.102), Drente.201
(D.201), Limburg.501 (L.501), Limburg.502
(L.502), Brabant.801 (B.801), Limburg.536
(L.536), Overijssel.728 (O.728) and
Utrecht.121 (U.121) and Czechoslovak
National Collection of Type Cultures of the
Institute of Hygiene and Epidemiology in
Deposit number CNCTC A07/80 in Prague, respectively.
CNCTC A08/80, CNCTC A09/80, CNCTC
A010/80, CNCTC A011/80, (Deposit date
March 6, 1980), CNCTC A016/80, CNCTC
A014/80, CNCTC A015/80 and CNCTC
Deposited as A013/80 (deposit date September 9, 1980) and also in the Collection Nationalede Cultures
Microorganismes d′Institut Pasteur, Paris
Deposit numbers I-111, I-112, I-113, and I, respectively.
-109, I-110 (Deposited date November 14, 1979)
and I-132, I-134, I-135 and I-133 (deposit date October 3, 1980). These nine new serotype virus strains all have the same “poultry infectious bronchitis virus [Avian
Infectious Bronchitis (IB) viris〕'' virus species. This virus species is a coronavirus with spikes on its surface and has a monophyletic RNA.
I'm curious about the type (Single Stranded RNA type).
However, all of the nine new serotype viruses listed above are
It is different from known serotype IB strains [Connecticut strain, Massachusetts strain, and H strain].
The nine strains also have mutually different properties. The above viruses were isolated from a flock of egg-laying chickens by the tracheaswab method (tracheaswab method).
That is, the flocks were vaccinated with the IBH120 and IBH52 vaccines twice and thrice, respectively.
This flock showed high body fluid antibody titers against IB virus. In addition, the above-mentioned viruses were isolated by this bacterial collection method from a young chicken, that is, a young chicken that had been previously inoculated with H120 type IB vaccine and showed respiratory symptoms in the latter half of fattening. Viruses thus isolated for both species of animals were given symbols within the range indicated by the national symbol system mentioned above. It has now been found that the virus strain isolated on the basis of attenuation with SPF-chicken embryos has largely lost its virulence to SPF chickens, yet still retains its immunizing potential. For example, the virus strain with the national symbol IBV Utrecht.101 shows the above characteristics even after 85 SPFI chicken embryo passages, and the IBV Limburg.536 virus strain shows the above characteristics even after 56 SPFI chicken embryo passages. The characteristics were shown. Surprisingly, in comparative studies using conventional H120 or H52 vaccines, the protective ability (measured as the amount of virus that neutralizes antibodies) against the Masachi Yusetsu type IB virus was significantly lower when the H type vaccine was replaced with, for example, a new type IB virus. IBV isolation of
It was found that administration of type H vaccine in combination with Utrecht 101 did not reduce it to a significant degree.
In one experiment, the experiment was initiated by administering the vaccine intranasally. For example, the neutralization index (Table 1) was obtained 4 weeks after administration of each vaccine and vaccine combination.

[Table] Not only the immune response but also the resistance to virus replication and persistence in and on the tracheal mucosa after administration of each of the above-mentioned vaccines and vaccine combinations was measured. This measurement is based on the virus reisolation method “Specifications for the production and
control of avian live virus vaccines”of the
Ministry of Agriculture, Fisheries and Food
of the United Kingdom Central Veterinary
Laboratory of Biological Products and
standards department, New Haw;
Weybridge, Surrey KT 153 NB, 2nd Edition
(1977), p.12. A cross-neutralization test using SPF chicken embryos and a cross-infection test using SPF chickens were conducted, and the results shown in Tables 2 and 3 were obtained: Four types of literature can be cited as references regarding the above cross-neutralization test and cross-infection test: (a ) K.Kume et al., Am.J.Vet.Res.41, (1) 97
−99 (1980). (b) LGRaggi et al.AVIAN DISEASES 19,
(2) 323−333 (1975). (c) R.Nielsen, Nord.Vet.Med.31, 407−413
(1979). (d) V.von Buelow, Centr.Blatt Vet.Med.
pp.151−162 (1967). The virus neutralization test is the preferred test method for serotyping IBV. Antibody variability of IBV strains is taken into account. Neutralization of the isolate with known IBV antiserum
Identify the isolate. A lack of neutralization indicates a different serotype of IBV or a virus other than IBV. Certain serovariant virus tests for virus neutralization form the standard for IBV. This test compares assay of virus in the presence of test serum to assay in the presence of an equal volume of diluent. Neutralization index (NI) is the concentration of virus in the diluted solution.
Determined by subtracting the log ₁₀ titer of virus in the test serum from the log ₁₀ titer. For example, Titer of virus in diluent = 10 ^7.2 Titer of virus in test serum = 10 ^3.4 Log ₁₀ difference (NI) 3.8 NI is interpreted as follows. That is, negative sera have an NI of 1.5 or less, and positive sera have an NI of 2.0 or more.
NI of 1.5 to 1.9 is suspicious. This test can be carried out using embryo-containing eggs or cell cultures used as assay systems. The use of microtiter cell cultures is described by Wooisy (Wooisy, RE, Brown, R.B.Davis, J.
L.Blue, and PDLukert, Comparison of a
microneutralization test in cell culture and
virus neutralization test in embryonated
eggs for determining infectious bronchitis
virus antibodies.J.Clin.Microbiol.3:149−
156.1976.) and has the advantage of preserving the reagents used in neutralization tests. Non-antibody inhibitors of IBV, which are stable at 56°C for 30 minutes and are present in many chicken sera, are probably responsible for the relatively high neutralization index of IBV negativity. The effects of these inhibitors can be reversed by adding 1.5% (w/v) sucrose or glucose to the virus serum mixture. To eliminate the effects of these inhibitors, serum should first be diluted 1:5 or 1:10 before use in the test.

[Table] H 〓7.2 neg neg
neg
U.101 neg 5.3 neg
neg
NI(10 ^x )
O.728 neg neg 5.8
neg
L.536 neg neg neg 〓
6.2

Claims (1)

[Claims] 1. Denoted by the Dutch national symbol Overijssel.728, Czechoslovak National Collection of
Type Culture of the Institute of Hygiene
and Epidemiology in Prague Deposit no.
As CNCTC A 015/80, also Collection
National Culture of Microorganisms
d′ Belongs to a new serotype characterized by the infectious bronchitis virus strain deposited at the Institut Pasteur, Paris, with accession number I.135,
Czechoslovak National Collection of Types
Culture of the Institute of Hygiene and
Deposit number CNCTC A in Epidemiology in Prague
As 015/80, also Collection Nationale de
Culture of Microorganismes d′ Institute
A poultry infectious bronchitis virus strain with a cross-neutralization index of 10 ^2.0 or higher against the infectious bronchitis virus deposited with Pasteur, Paris under accession number I.135. 2 Denoted by the Dutch national symbol Overijssel.728, Czechoslovak National Collection of
Type Culture of the Institute of Hygiene
and Epidemiology in Prague Deposit no.
As CNCTC A 015/80, also Collection
Nationale de Culture de Microorganismes
A poultry infectious bronchitis virus strain according to claim 1, deposited with the d'Institut Pasteur, Paris, under deposit number I.135.