Oral tolerance is defined by the inhibition of immune responsiveness to a protein previously exposed via the oral route. Protein antigens exposed via the oral route can be absorbed through the mucosal surfaces of the gastrointestinal tract and can make physical contact with immune cells residing in the intestinal lamina propria (LP). However, the mechanisms of oral tolerance and immune regulation in the intestines currently remain to be clearly elucidated.

In order to determine the effect of oral protein antigen intake (ovalbumin, OVA) on the intestinal LP, we assessed the expression profile of the T cell receptor and the co-receptors on the cells from the intestines of the tolerant and immune mouse groups.

We determined that the proportion of OVA-specific B cells and γδ T cells had decreased, but the CD8αβ and CD8αα T cells were increased in the LP from the tolerant group. The proportion of CD8+ T cells in the spleen did not evidence any significant differences between treatment groups.

These results indicate that CD8+ T cells in the intestinal LP may perform a regulatory role following antigen challenge via the oral route.