Interleukin-18-mediated enhancement of the protective effect of an infectious laryngotracheitis virus glycoprotein B plasmid DNA vaccine in chickens.
The immunogenicity of an infectious laryngotracheitis virus (ILTV) glycoprotein B (gB) plasmid DNA vaccine and the immunoregulatory activity of chicken interleukin-18 (IL-18) were investigated in a challenge model. Two recombinant plasmids, pcDNA3.1/gB (pgB) and pcDNA3.1/IL-18 (pIL-18), containing gB and IL-18 were constructed. Chickens were intramuscularly administered two immunizations 2&emsp14;weeks apart, and challenged with the virulent CG strain of ILTV 2&emsp14;weeks later. All animals vaccinated with pgB alone or with a combination of pgB plus pIL-18 developed a specific anti-ILTV ELISA antibody and splenocyte proliferation response. The ratios of CD4(+) to CD8(+) T lymphocytes in chickens immunized with pgB plus pIL-18 were significantly higher than in those immunized with pgB alone. Co-injection of pIL-18 significantly increased the production of gamma interferon and IL-2, indicating that IL-18 enhances the T helper 1-dominant immune response. Challenge experiments showed that the morbidity rate in the pgB group (25  %) was significantly higher than that in the pgB plus pIL-18 group (10  %). The mortality rates in the pgB and pgB plus pIL-18 groups were 10 and 0 %, respectively, and the corresponding protection rates were 60 and 80  %. These results indicate that IL-18 may be an effective adjuvant for an ILTV vaccine.
Chen
Hong-Ying
HY
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Zhang
Hong-Ying
HY
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Li
Xin-Sheng
XS
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Cui
Bao-An
BA
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Wang
Shu-Juan
SJ
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Geng
Jing-Wei
JW
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
Li
Kun
K
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95, 450002 Zhengzhou, Henan, PR China.
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D016516:CD4-CD8 Ratio; D049109:Cell Proliferation; D002645:Chickens; D016207:Cytokines / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006566:Herpesviridae Infections / Q000401:mortality / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D001352:Herpesvirus 1, Gallid / Q000235:genetics / Q000276:immunology; D007117:Immunization, Secondary / Q000379:methods; D007273:Injections, Intramuscular; D020382:Interleukin-18 / Q000235:genetics / Q000276:immunology*; D010957:Plasmids / Q000008:administration & dosage; D016133:Polymerase Chain Reaction / Q000379:methods; D011201:Poultry Diseases / Q000401:mortality / Q000473:pathology / Q000517:prevention & control*; D016019:Survival Analysis; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014132:Trachea / Q000821:virology; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
D000914:Antibodies, Viral; D016207:Cytokines; D004279:DNA, Viral; D020382:Interleukin-18; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C067381:GB protein, Infectious laryngotracheitis virus