RT-PCR detection of cytokine expression in gastric mucosae of mice with Helicobacter heilmannii infection / 中华微生物学和免疫学杂志

ABSTRACT

Objective To compare the changes in IFN-γ, IL-4, IL-10 and IL-1β expression at mRNA level in gastric mucosae of BALB/c, C57BL/6 and nude mice at different stages of Helicobacter heilmannii ( H. heilmannii) infection, and to investigate the types of induced immune responses. Methods Each kind of mice was randomly divided into two groups infection ( n=30 ) and control ( n=6 ) groups. Those in the infection groups were intragastrically inoculated with H. heilmannii strains to establish long-term stable mouse infection models. Gastric mucosa tissues were collected at weeks 4, 8, 12, 24 and 36 and ana-lyzed by semi-quantitative RT-PCT to detect the expression of IFN-γ, IL-4, IL-10 and IL-1βat mRNA lev-el. Results In the early stage of infection (weeks 4-12), INF-γ, IL-4, IL-10, and IL-1β expression at mRNA level in the gastric mucosae of BALB/c and C57BL/6 mice were significantly increased compared with those of the control groups (P<0. 05). IL-4, IL-10 and IFN-γexpression peaked at weeks 8-12, while IL-1βexpression reached the peak at week 4. After 12 weeks, IFN-γexpression at mRNA level in BALB/c mice was significantly decreased, but showed no significant change in C57BL/6 mice. IL-4 expression at mRNA level in C57BL/6 mice at the late stage of infection (week 36) was lower than that in the correspond-ing control group (P<0. 05). Expression of IFN-γ, IL-4, IL-10 and IL-1β at mRNA level in nude mice were all higher than those in the control group, and there were significant differences in IL-1βand IL-4 ex-pression between groups (P<0. 05). Conclusions Expression of cytokines in H. heilmannii-infected mice increased over time. IFN-γ-mediated Th1 immune responses were the predominant immunity induced by H. heilmannii infection. Immune responses to H. heilmannii infection varied with the kinds of mice. C57BL/6 mice showed mainly Th1 cell immune responses, while Th1/Th2 mixed immune responses were induced in BALB/c mice.