with a decrease in TCRγδ-T cells

We have already reported that WBB6F1-W/W-v (W/W-v) mice, which have mutations in the c-kit gene, are highly susceptible to oral sensitization, and that the proportion of TCR gamma delta-T cells among the intraepithelial lymphocytes (IELs) (gamma delta-IELs) of W/W-v is much lower than in congenic wild-type (+/+) mice. In this study we examined an inhibitory role of gamma delta-IELs in oral sensitization using two different methods. First, wild-type (+/+) mice were sensitized by oral administration of 1.0 mg ovalbumin (OVA) by gavage every day for 9 weeks after anti-TCR gamma delta antibody treatment 4 times. The treatment resulted in an enhanced OVA-specific IgG1 antibody production, active systemic anaphylaxis (ASA), and Th2-dominant cytokine production. Next, W/W-v mice whose bone marrow cells were reconstituted from C57BL/6J mice for 5 months were sensitized by oral administration of OVA. The OVA-specific IgG1 antibody titer in the bone marrow-reconstituted W/W-v mice was neither significantly enhanced, nor ASA was induced. The proportion of gamma delta-IELs in the reconstituted mice was much higher than that in the untreated W/W-v mice. The above findings suggest that the decrease or increase in number of gamma delta-IELs enhances or decreases oral sensitization respectively. These results show that gamma delta-IELs have an important role in the oral tolerance to food antigens.