OBJECTIVETo investigate the effects of adipose-derived stem cells (ADSC) and non-methylated CpG-oligodeoxynucleotides (CpG-ODN) on the expression of peripheral blood CD4CD25regulatory T (Treg) cells in young mice with food allergy, as well as their immune intervention effects.

METHODSA total of 40 female BALB/c mice were randomly divided into control group, allergic group, ADSC treatment group, and CpG-ODN treatment group, with 10 mice in each group. A mouse model of food allergy was established by intraperitoneal injection and intragastric administration of ovalbumin (OVA) for sensitization and challenge. The mice in the control group were treated with normal saline at the same dose; the mice in the ADSC treatment group were given intraperitoneal injection of ADSC (1×10cells for each mouse) before and after OVA challenge, and those in the CpG-ODN treatment group were given intraperitoneal injection of non-methylated CpG-ODN solution (40 μg for each mouse) at 1 hour before challenge by gavage. The allergic symptom scores were determined for each group after model establishment. ELISA was used to measure the serum level of OVA-IgE. Flow cytometry was used to measure the percentage of peripheral blood CD4CD25Treg cells. Hematoxylin and eosin staining was used for the pathological analysis of the jejunum.

RESULTSThe allergic group had significantly higher allergic symptom scores and serum level of OVA-IgE than the control group (P<0.05). There were no significant differences in the allergic symptom score and the serum level of OVA-IgE between the ADSC treatment group and the CpG-ODN treatment group (P>0.05), but these two groups had significantly lower allergic symptom scores and serum level of OVA-IgE than the allergic group and significantly higher allergic symptom scores and serum level of OVA-IgE than the control group (P<0.01). The allergic group had a significantly lower percentage of peripheral blood CD4CD25Treg cells than the control group (P<0.05). The ADSC treatment group and the CpG-ODN treatment group had a significantly higher percentage of peripheral blood CD4CD25Treg cells than the allergic group (P<0.05); there were no significant differences between these two groups or between them and the control group (P>0.05). Pathological results showed structural damage and edema in the jejunal villi, a large number of eosinophils, and lymphocyte infiltration in the allergic group, while the ADSC treatment group and the CpG-ODN treatment group had less structural damage and edema in the jejunal villi, a lower number of eosinophils, and less lymphocyte infiltration.

CONCLUSIONSADSC and non-methylated CpG-ODN have a certain effect in the treatment of food allergy and can increase the percentage of peripheral blood CD4CD25Treg cells and reduce the level of OVA-IgE. They may be associated with the induction of immune tolerance and these two treatment have comparable effects. Detailed mechanisms of action still need further investigation.