Th immune response induced by H pylori vaccine with chitosan as adjuvant and its relation to immune protection.
OBJECTIVE
To study the immunological protective effect of H pylori vaccine with chitosan as an adjuvant and its mechanism.


METHODS
Female BALB/c mice were randomly divided into seven groups and orally immunized respectively with PBS, chitosan solution, chitosan particles, H pylori antigen, H pylori antigen plus cholera toxin (CT), H pylori antigen plus chitosan solution, H pylori antigen plus chitosan particles once a week for four weeks. Four weeks after the last immunization, the mice were challenged twice by alive H pylori (1 x 10(9) CFU/mL) and sacrificed. Part of the gastric mucosa was embedded in paraffin, cut into sections and assayed with Giemsa staining. Part of the gastric mucosa was used to quantitatively culture H pylori. ELISA was used to detect cytokine level in gastric mucosa and anti- H pylori IgG1, IgG2a levels in serum.


RESULTS
In the groups with chitosan as an adjuvant, immunological protection was achieved in 60% mice, which was significantly higher than in groups with H pylori antigen alone and without H pylori antigen (P < 0.05 or 0.001). Before challenge, the level of IFN and IL-12 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in the control group and the group without adjuvant (P < 0.05 or 0.005). After challenge, the level of IFN and IL-12 was significantly higher in the groups with adjuvant than in the groups without adjuvant and antigen (P < 0.05 or 0.001). Before challenge, the level of IL-2 in gastric mucosa was not different among different groups. After challenge the level of IL-2 was significantly higher in the groups with adjuvant than in the control group (P < 0.05 or 0.001). Before challenge, the level of IL-10 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant (P < 0.05 or 0.01). After challenge, the level of IL-10 was not different among different groups. Before challenge, the level of IL-4 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant (P < 0.05). After challenge, the level of IL-4 was significantly higher in the groups with chitosan particles as an adjuvant than in the group with CT as an adjuvant (P < 0.05), and in the group with chitosan solution as an adjuvant, the level of IL-4 was significantly higher than that in control group, non-adjuvant group and the groups with CT (P < 0.05 or 0.001). The ratio of anti- H pylori IgG2a/IgG1 in serum was significantly lower in the groups with chitosan as an adjuvant than in the groups with CT as an adjuvant or without adjuvant (P < 0.01).


CONCLUSIONS
H pylori vaccine with chitosan as an adjuvant can protect against H pylori infection and induce both Th1 and Th2 type immune response.
Xie
Yong
Y
Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
Zhou
Nan-Jin
NJ
Gong
Yan-Feng
YF
Zhou
Xiao-Jiang
XJ
Chen
Jiang
J
Hu
Si-Juan
SJ
Lu
Nong-Hua
NH
Hou
Xiao-Hua
XH
D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology / Q000378:metabolism; D000942:Antigens, Bacterial / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology* / Q000627:therapeutic use; D048271:Chitosan / Q000008:administration & dosage*; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D016753:Interleukin-10 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011897:Random Allocation; D018417:Th1 Cells / Q000276:immunology / Q000473:pathology; D018418:Th2 Cells / Q000276:immunology / Q000473:pathology
D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D007074:Immunoglobulin G; D016753:Interleukin-10; D015847:Interleukin-4; D048271:Chitosan