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US3981771A
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Marek's disease vaccine
Assignee: Individual
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Filing: 1975-05-29
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Granted: 1976-09-21
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Expires: 1995-05-29
Abstract
Abstract A vaccine for immunizing poultry against Marek's disease (Type II leukosis), processes for producing same, and methods of immunizing poultry flocks. The vaccine is obtained by modifying the JM strain of Marek's disease by rapid serial passage through selected tissue of live chickens until highly virulent followed by attenuation thereof in avian embryos.
Inventors
- 👤 Martin Sevoian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:30
CPC Classifications
A; A61; A61K; A61K39/00; A61K39/12; A61K39/245; A61K39/255; A61K2039/51; A61K2039/525; A61K2039/5254; A61K2039/55; A61K2039/552; C; C12; C12N; C12N2710/00; C12N2710/00011; C12N2710/16011; C12N2710/16311; C12N2710/16334
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
172 words
Process for preparing vaccine for immunizing poultry against JM and serologically like strains of Marek's disease comprising the steps of producing a virulent strain of modified Marek's disease virus (JM-V) by the multiple serial passage of JM strain of field Marek's disease virus through humoral antibody producing tissue of live young chicks, continuing said serial passage until said virus becomes highly immunogenic and pathogenic as evidenced by lymphoblastic leukemia and mortality of birds within ten days postinoculation, the immunogenicity of said modified virus (JM-V) being evidenced by development in chickens inoculated with the modified virus of antibody levels in the range of 10-350 serum neutralization titers per milliliter, and thereafter attenuating the pathogenicity of said modified virus by serially passing the same through yolk sacs of avian embryos until a vaccine is obtained which is non-contagious, aviremic and non-pathogenic or substantially so but remains highly immunigenic to Marek's disease virus, whereby poultry inoculated with said vaccine is able to withstand infectous challenge of said JM-V and JM strain of Marek's disease virus.
Claim 2
Dependent Claim
172 words
Process for preparing vaccine for immunizing poultry against JM and serologically like strains of Marek's disease comprising the steps of producing a virulent strain of modified Marek's disease virus (JM-V) by the multiple serial passage of JM strain of field Marek's disease virus through humoral antibody producing tissue of live young chicks, continuing said serial passage until said virus becomes highly immunogenic and pathogenic as evidenced by lymphoblastic leukemia and mortality of birds within ten days postinoculation, the immunogenicity of said modified virus (JM-V) being evidenced by development in chickens inoculated with the modified virus of antibody levels in the range of 10-350 serum neutralization titers per milliliter, and thereafter attenuating the pathogenicity of said modified virus by serially passing the same through yolk sacs of avian embryos until a vaccine is obtained which is non-contagious, aviremic and non-pathogenic or substantially so but remains highly immunigenic to Marek's disease virus, whereby poultry inoculated with said vaccine is able to withstand infectous challenge of said JM-V and JM strain of Marek's disease virus.
Claim 3
Dependent Claim
87 words
Process of preparing vaccine for immunizing poultry as set forth in claim 1 wherein said highly pathogenic agent is obtained by the multiple passage of JM strain field Marek's disease virus through live chickens for at least 100 passages, the first several of said passages involving the use of said selected tissues, the blood of said chickens being used for the remainder of said passages, and in which the attenuation of said highly pathogenic agent is carried out by at least 40 serial passages through avian embryos.
Claim 4
Dependent Claim
124 words
Process of preparing vaccine for immunizing poultry as set forth in claim 1 wherein said JM strain field Marek's disease virus is rendered highly immunogenic and pathogenic by the rapid multiple serial passage through tissues extracted from live chickens infected with Marek's disease virus of one or more of the following organs in which antibodies are produced: spleen, bone marrow, liver and kidneys; using such tissues for a number of said serial passages and for the remainder of said serial passages using whole blood extracted from moribund chickens until said agent becomes highly immunogenic and pathogenic and thereafter attenuating the pathogenicity of said modified virus by serially passing the same through yolk sacs of avian embryos, each passage being 5 to 10 days duration.
Claim 5
Dependent Claim
24 words
Process of preparing vaccine for immunizing poultry as set forth in claim 1 wherein said highly pathogenic agent is designated by ATCC No. VR-736.
Claim 6
Dependent Claim
54 words
Process of preparing vaccine for immunizing poultry as set forth in claim 1 wherein the embryo material is harvested about one week after inoculation with the agent and is repassed into the yolk sac of avian embryos for about 1 week per passage until a material is obtained which is non-pathogenic for day-old chicks.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-21 | 1980-03-22 | 1980-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-21 | 1984-03-22 | 1984-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-21 | 1988-03-22 | 1988-09-21 | $7700.00 | Window Closed / Lapsed |