Protection against very virulent infectious bursal disease virus in chickens immunized with DNA vaccines

• Published in: Veterinary microbiology 2004-06, Vol.101 (1), p.39-51
• Main Authors: Kim, Soo Joung, Sung, Haan Woo, Han, Jeong Hee, Jackwood, Daral, Kwon, Hyuk Moo
• Format: Article
• Language: English
• Subjects: Animals; antibodies; Antibodies, Viral - blood; atrophy; Biological and medical sciences; Birnaviridae Infections - immunology; Birnaviridae Infections - prevention & control; Birnaviridae Infections - veterinary; Birnaviridae Infections - virology; Bursa of Fabricius - virology; Cell Division - immunology; cell proliferation; Chickens; DNA vaccine; enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - veterinary; Fundamental and applied biological sciences. Psychology; humoral immunity; IBDV; immune response; Infectious bursal disease virus; Infectious bursal disease virus - immunology; Infectious bursal disease virus - pathogenicity; Lymphocyte Activation - immunology; lymphocyte proliferation; Lymphocyte proliferation assay; lymphocytes; Microbiology; Miscellaneous; plasmids; Poultry Diseases - immunology; Poultry Diseases - prevention & control; Poultry Diseases - virology; Random Allocation; recombinant vaccines; Specific Pathogen-Free Organisms; survival rate; T-Lymphocytes - cytology; T-Lymphocytes - immunology; T-Lymphocytes - virology; transfection; translation (genetics); vaccination; Vaccination - methods; Vaccination - veterinary; Vaccines, DNA - immunology; Vaccines, DNA - therapeutic use; viral proteins; Viral Vaccines - immunology; Viral Vaccines - therapeutic use; Virology; Virulence
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2004.03.009

Plasmid DNA vaccines pcDNA-VP2 expressing only VP2 protein and pcDNA-VP243 expressing VP2, VP4 and VP3 proteins of very virulent infectious bursal disease virus (vvIBDV) Korean SH/92 strain were constructed. The expression of viral proteins from constructed DNA vaccines was confirmed by an in vitro transcription/translation system and transfection in COS-7 cells. To investigate the protective efficacy of these DNA vaccines, 2-week-old chickens were injected intramuscularly and intraperitoneally with pcDNA-VP2 and pcDNA-VP243 twice at 2-week intervals. On week 2 after the second immunization, chickens were orally challenged with the vvIBDV SH/92 strain and observed for 10 days. Antibodies specific to IBDV were not detected by enzyme-linked immunosorbent assay in DNA vaccination groups before challenge but were induced after challenge. The immunized groups exhibited a higher survival rate and lower bursal atrophy as compared with the non-immunized groups after challenge. The survival rates of pcDNA-VP243 and pcDNA-VP2 groups were 70 and 50%, respectively, but the survival rate of challenge control group was only 10%. In the ConA-induced lymphocyte proliferation assay of peripheral blood and splenic lymphocytes, the immunized groups showed significantly higher proliferation responses ( P