Enhancement of immunity to an Escherichia coli vaccine in mice orally inoculated with a fusion gene encoding porcine interleukin 4 and 6.
Experiments were conducted to investigate the effect of a fusion gene of porcine IL-4 and IL-6 (PIL4/IL6) packaged with chitosan nanoparticles (CNPs) in terms of the development of a novel effective adjuvant. The IL4/PIL6 fusion gene was constructed and inserted into a eukaryotic expression vector. The plasmid was bound to CNP and then utilized to orally inoculate 21-day-old female Kunming mice that simultaneously received intramuscular injection of inactivated Escherichia coli vaccine. At 35 days post-vaccination, the mice were challenged by oral feeding with virulent O139: K88 strain EPEC E. coli bacteria. Compared with those of control mice, the content of immunoglobulins and specific antibodies to E. coli increased significantly in the sera of mice immunized with VPIL4/IL6-CNP (P<0.05). Furthermore, the levels of IL-2, IL-4 and IL-6 increased remarkably in the sera of immunized mice (P<0.05). After challenge, these immunological markers were elevated to different degrees in the mice immunized with the fusion gene construct (IL4/VPIL6-CNP) or individual plasmids (VPIL4+VPIL6-CNP). The immunized mice all survived the challenge and did not show any symptoms or lesion, whereas the VR1020-CNP control mice manifested obvious clinical symptoms and hemorrhagic lesions in the digestive tracts. These results demonstrated that VPIL4/IL6 entrapped with CNP is a novel promising adjuvant to promote specific immunity and resistance of animals against infectious pathogen.
Zhang
Huan
H
Key Laboratory for Bio-Resource and Eco-Environment of Ministry Education, Bioengineering Research Center for Animal Disease Prevention and Control, Life Science College, Sichuan University, Chengdu 610064, Sichuan, PR China.
Cheng
Chi
C
Zheng
Min
M
Chen
Jian-Lin
JL
Meng
Ming Jie
MJ
Zhao
Zhong-Zhong
ZZ
Chen
Qian
Q
Xie
Zhao
Z
Li
Jiang Ling
JL
Yang
Yi
Y
Shen
Yi
Y
Wang
Hong-Ning
HN
Wang
Ze-Zhou
ZZ
Gao
Rong
R
D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D048271:Chitosan / Q000008:administration & dosage; D016207:Cytokines / Q000097:blood; D004927:Escherichia coli Infections / Q000276:immunology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D041981:Gastrointestinal Tract / Q000473:pathology; D015847:Interleukin-4 / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D015850:Interleukin-6 / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D051379:Mice; D053758:Nanoparticles / Q000008:administration & dosage; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
D000907:Antibodies, Bacterial; D016207:Cytokines; D022361:Escherichia coli Vaccines; D015850:Interleukin-6; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; D015164:Vaccines, Inactivated; D014614:Vaccines, Synthetic; D015847:Interleukin-4; D048271:Chitosan