SC9-2 is a recombinant Marek's disease virus (MDV) strain lacking the meq oncogene. Previous study demonstrated that SC9-2 virus provides good protection against challenge with a very virulent MDV rMd5, but it induces immunosuppressive effects in specific pathogen-free (SPF) chickens. In the present study, SC9-2 was serially passaged on chicken embryo fibroblast (CEF) cell cultures. The pathogenicity and immune efficacy of SC9-2/10 and SC9-2/40 against rMd5 were evaluated. Animal experimental results showed that SC9-2/10 and SC9-2/40 showed no lethality or tumorigenicity in SPF chickens. Body weight of chickens inoculated with SC9-2/40 were significantly higher than that of the chickens inoculated with SC9-2/10 but lower than that of the uninoculated controls. The severity of bursa and thymus atrophy (BTA) and spleen enlargement in SC9-2/40-inoculated chickens were also weaker than the SC9-2/10-inoculated ones but stronger than the uninoculated controls. Chickens inoculated with SC9-2/40 and SC9-2/10 showed similar antibody levels induced by H9N2 subtype avian influenza virus/Newcastle disease virus inactivated vaccines, both of which were lower than the uninoculated controls. Replication of SC9-2/40 was significantly lower than SC9-2/10 in feather follicle epithelium (FFE) of infected chickens. The immune protection index of SC9-2/40 was also lower than that of SC9-2/10, but the difference was not significantly, and both of which were significant higher than that of the commercial MDV vaccine CVI988/Rispens. The results of our studies demonstrated that SC9-2/40 showed weaker severity of BTA, spleen enlargement, and body weight loss and lower replication level in FFE than SC9-2/10 in SPF chickens. However, SC9-2/40 was able to confer better immune protection as compared with CVI988/Rispens vaccination in SPF chickens. In conclusion, serially attenuation of SC9-2 in CEFs reduced the lymphoid organ atrophy and replication in SPF chickens, and the immune protective efficacy of attenuated viruses was still superior than CVI988/Rispens.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587640 | PMC |
| http://dx.doi.org/10.1016/j.psj.2019.11.059 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Co-infections of and various avian pathogens resulted in varying rates of SPF broilers with an infection.
Avian Pathol
January 2025
Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.
infections can be experimentally reproduced after oral inoculation. Co-infections of with other avian pathogens might increase the proportion of broilers with infections. The aim of the study was to examine via which infection route is capable of causing infections and which co-infections exacerbate infections.
View Article and Find Full Text PDFEffects of and on the duodenal development of specific-pathogen-free broiler chickens.
Vet World
November 2024
Preclinical Institute, Faculty of Veterinary Medicine, Latvia University of Life Sciences and Technologies, Jelgava, Latvia.
Background And Aim: The positive effects of and on growth and feed consumption indicators have been described; however, the underlying mechanisms remain unclear. This study aimed to determine whether the addition of CNCM-I-3699 (2.10 GU/g) and CNCM-I-3698 (2.
View Article and Find Full Text PDFCombination Adjuvants Enhance Recombinant H5 Hemagglutinin Vaccine Protection Against High-Dose Viral Challenge in Chickens.
Vaccines (Basel)
December 2024
College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
Background: Recombinant avian influenza subunit vaccines often require adjuvants to enhance immune responses. This study aims to evaluate the immune-enhancing potential of seven combination adjuvants in specific pathogen-free (SPF) chickens.
Methods: SPF chickens were vaccinated with combinations of ISA78VG and adjuvants, including Quil-A, CpG, and monophosphoryl lipid A (MPLA).
A novel approach for efficient co-expression of two foreign genes based on the reverse genetic system of Newcastle disease virus.
Front Microbiol
December 2024
Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China.
Article Synopsis
- Newcastle disease virus (NDV) serves as a valuable model for studying viral mechanisms and is being utilized as a vector for vaccine development and cancer therapy.
- A reverse genetic system was created for the NDV Mukteswar strain, allowing for the insertion of the enhanced green fluorescent protein (EGFP) gene between the P and M genes to form a stable transcription unit that expresses exogenous genes over multiple generations.
- Through this system, a recombinant virus that co-expresses EGFP and cherry fluorescent protein (CFP) was developed, demonstrating efficient simultaneous expression of both proteins, though with slight differences in expression levels, and similar growth rates with mild virulence attenuation compared to the original strains.
Onset and long-term duration of immunity provided by a single vaccination with recombinant a Marek's disease virus with REV-LTR insertion.
Front Vet Sci
December 2024
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
Marek's Disease (MD), caused by Marek's disease virus (MDV), is a highly contagious lymphoproliferative disease in poultry. Despite the fact that MD has been effectively controlled by vaccines, the virulence of field isolates of MDV has continued to evolve, becoming more virulent under the immune pressure of vaccines. Our previous research has confirmed that the recombinant rMDV strain with REV-LTR insertion can be used as a live attenuated vaccine candidate.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!