ABSTRACT
BACKGROUND AND OBJECTIVE: Murine system for studying allergic diseases has been popular in the fields of food allergy and development of their therapeutic strategies. However, there has been no information about the age-dependent changes of natural immune responses of naive C3H/HeJ mice. The purpose of this study was to evaluate the age-dependent changes of B and T-cell mediated immunologic parameters in naive C3H/HeJ mice, which can provide information for experimental planning and analysis of research results. SUBJECTS AND METHODS: Eight naive, female, 5-week-old C3H/HeJ mice were grown under the regular mouse chow feeding conditions for 6 weeks. Sera were obtained at week (w) 5, w6, w8 and w10 for measuring total and chow-specific IgE, IgG1 and IgG2a antibodies. Splenocyte proliferation (at w8 and w10) and cytokine production (at w6, w8 and w10) were evaluated with or without Con A stimulation with pooled splenocytes from two mice of each age group. Serum antibodies and cytokines (IL-4, IL-5, IL-12, INF-gamma, TGF-beta1) were measured by ELISA. Using RT-PCR, IL-4 and INF-gamma mRNA expressions were measured in Peyer's patch and spleen tissue at w10. RESULTS: The levels of total IgE and IgG1 were increased by age while the level of IgG2a was decreased. Chow-specific IgE and IgG2a responses were neglectable through out the whole experimental period (20-30 ng/ml or less). Chow-specific IgG1 levels were measured in the significant concentrations (200-300 ng/ml) but there was no age-dependent change through out the experiment. Con A stimulated-splenocyte proliferation indexes were variable according to the culture-durations and ages of mice. The higher proliferation indexes were observed in the wells receiving thymidine pulse at 48-hour culture, especially in the mice at w10. Con A stimulated IL-4 production in the 72-hour splenocyte culture supernatant was significantly increased at w8, and w10 while INF-gamma production increased only at w10. The changes in the production of IL-5, IL-12 and TGF-beta did not provide significant information in the present study. The ratio of IL-4/IFN-gamma mRNA expression was higher in Peyer's patch than in the spleen. CONCLUSION: The changes of B-cell and T-cell mediated immunologic parameters were complex and variable according to the age in naive C3H/HeJ mice under regular chow feeding conditions. For that reason, the information from the present study needs to be considered in the course of planning or analysing research/data using murine systems.