SUPPRESSION OF THE ALLERGIC REACTION IN A FOOD ALLERGY MOUSE MODEL THROUGH THE ORAL ADMINISTRATION OF HEAT-KILLED Tsukamurella inchonensis

Food allergy, a worldwide immune adverse reaction to certain foods, is a growing clinical concern with no approved standardized immunotherapy. In this work we aimed to modulate milk allergy in a mouse model through the oral administration of a heat-killed Actinomyces bacteria (Tsukamurella inchonensis-Ti).

Balb/c mice were sensitized with cow´s milk proteins (CMP) plus cholera toxin by gavage, and orally challenged with CMP to evidence hypersensitivity. Thereafter, Ti was orally administered during two months for immunomodulation. Mice were challenged and treatment efficacy was in vivo (clinical score and cutaneous test) and in vitro (serum specific antibodies and cytokines by ELISA, and cell analysis by flow cytometry) evaluated.

Clinical signs and serum specific IgE levels were lower in Ti-treated mice compared with sensitized mice (p<0.05), with a concomitant reduction of IL-4 and IL-5. Ti-treated mice showed a reduction of intestinal CD4⁺ CD25⁺ CD69⁺ Teff cells with an increased frequency of lamina propria CD4⁺ CD25⁺ FoxP3⁺ T cells (9.61±2.15% vs 6.15±0.25% Ti-treated and Sensitized, respectively). Intestinal IL-10 and IL-10⁺ FoxP3⁺ T cells were up-regulated.

In conclusion, Ti induced Treg that controlled the Th2-medited allergic responses, with suppression of IgE. These findings may constitute the basis for a potential immunotherapy for food allergies.