Enhancement of the immunogenicity of an infectious laryngotracheitis virus DNA vaccine by a bicistronic plasmid encoding glycoprotein B and interleukin-18.
A DNA vaccine against infectious laryngotracheitis virus (ILTV) can induce specific humoral and cell-mediated immunity. However, compared to conventional vaccines, DNA vaccines usually induce poor antibody responses. To determine if co-expression of a cytokine can result in a more potent ILTV DNA vaccine, immunogenicity and protective efficacy of a monocistronic vector encoding the glycoprotein B (gB) of ILTV was compared to that of a bicistronic vector separately encoding the gB and chicken interleukin-18. Humoral and cellular responses induced by the DNA vaccines administered to the quadriceps muscle of chickens were evaluated. There were significant differences in antibody levels elicited by either monocistronic or bicistronic DNA vaccines as determined by ELISA. The percentages of CD3(+), CD3(+)CD8(+) and CD3(+)CD4(+) subgroups of peripheral blood T-lymphocytes in chickens immunized with the bicistronic DNA vaccine were higher than those in chickens immunized with monocistronic DNA vaccine. When chickens were challenged with a virulent CG strain of ILTV, the protective efficacy was enhanced significantly after immunization with the bicistronic DNA vaccine. These results demonstrated that co-expression of an adjuvant cytokine from a bicistronic DNA vaccine may be an effective approach to increasing ILTV DNA vaccine immunogenicity.
Chen
Hong-Ying
HY
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95#, 450002 Zhengzhou, Henan Province, People's Republic of China. chhy927@126.com
Zhao
Li
L
Wei
Zhan-Yong
ZY
Cui
Bao-An
BA
Wang
Zhen-Ya
ZY
Li
Xin-Sheng
XS
Xia
Ping-An
PA
Liu
Jin-Peng
JP
D000276:Adjuvants, Immunologic / Q000235:genetics / Q000494:pharmacology*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay; D001352:Herpesvirus 1, Gallid / Q000235:genetics / Q000276:immunology*; D007273:Injections, Intramuscular; D020382:Interleukin-18 / Q000235:genetics / Q000494:pharmacology*; D016019:Survival Analysis; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*
D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D020382:Interleukin-18; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; C067381:GB protein, Infectious laryngotracheitis virus