Oral tolerance is inducible during active dextran sulfate sodium-induced colitis

AIM:To investigate whether oral tolerance is inducible during the active phase of dextran sulfate sodium(DSS)-induced colitis.METHODS:Colitis was induced in 6-to 8-wk-old female BALB/c mice by the administration of 2%DSS.To induce oral tolerance,mice that received water with DSS[DSS(+)]and mice that received autoclaved water[DSS(-)]were intragastrically(i.g.)administered ovalbumin(OVA)as a tolerogen before systemic challenge with OVA.Following this,serum levels of OVA-specific Ig E antibodies were measured.In mice with activecolitis,CD4+CD25+Foxp3+cell and B10 cell frequencies were evaluated using flow cytometry.Cytokine m RNA expression profiles were evaluated by reverse transcription real-time polymerase chain reaction.RESULTS:Regardless of the presence of DSS colitis,OVA-specific immunoglobulin E concentrations were significantly reduced in mice that were i.g.administered OVA compared to mice that were i.g.administered PBS[DSS(+):4.4(4.2-9.5)ng/m L vs 83.9(66.1-123.2)ng/m L,P<0.01;DSS(-):27.7(0.1-54.5)ng/m L vs116.5(80.6-213.6)ng/m L,P<0.01].These results demonstrated that oral tolerance was induced in both the presence and absence of colitis.In the spleen and mesenteric lymph nodes(MLN),the frequencies of CD4+CD25+Foxp3+cells and B10 cells,both of which are associated with oral tolerance,did not significantly change.In the spleen,interferon-γm RNA expression significantly decreased in mice with colitis[DSS(+):0.42(0.31-0.53)vs DSS(-):1.00(0.84-1.39),P<0.01].The expression levels of other cytokines did not significantly change.CONCLUSION:Oral tolerance is inducible during active DSS colitis.The stability of regulatory cell populations in the spleen and MLN in colitis might correlate with these results.