Regulating effects of novel CpG chitosan-nanoparticles on immune responses of mice to porcine paratyphoid vaccines.
OBJECTIVE
To study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles (CNP) with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines.


METHODS
A novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 (IL2), IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation.


RESULTS
This CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control (P < 0.05). Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice (P < 0.05). IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice (P < 0.05). The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number (P < 0.05). After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum.


CONCLUSIONS
CpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine.
Fu
Man-Liang
ML
Key Lab. for Bio-Resource and Eco-Environment of Education Ministry, Life Science College, Sichuan University, Chengdu 610064, Sichuan, China.
Ying
San-Cheng
SC
Wu
Mei
M
Li
Hui
H
Wu
Kai-Yuan
KY
Yang
Yi
Y
Zhang
Huan
H
Cheng
Chi
C
Wang
Ze-Zhou
ZZ
Wang
Xiu-Ying
XY
Lv
Xue-Bing
XB
Zhang
Yi-Zheng
YZ
Gao
Rong
R
D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D049109:Cell Proliferation; D048271:Chitosan / Q000737:chemistry*; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D007132:Immunoglobulin Isotypes / Q000097:blood; D007378:Interleukins / Q000097:blood; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000166:cytology; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage / Q000494:pharmacology*; D010284:Paratyphoid Fever / Q000276:immunology* / Q000517:prevention & control; D012475:Salmonella / Q000502:physiology; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000517:prevention & control; D013552:Swine / Q000276:immunology; D014436:Typhoid-Paratyphoid Vaccines / Q000276:immunology*
D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; C408982:CPG-oligonucleotide; D007132:Immunoglobulin Isotypes; D007378:Interleukins; D009838:Oligodeoxyribonucleotides; D014436:Typhoid-Paratyphoid Vaccines; D048271:Chitosan