Prebiotic oligosaccharides reduce casein sensitization in mice: A possible role for regulatory T cells

Oligosaccharides (OS) in human milk are thought to protect the neonate from development of allergies. In this study the effects of dietary supplementation with a prebiotic mixture on casein sensitization in mice was studied and the contribution of regulatory T-cells was addressed. For a period of 5 weeks, female C3H/HeOuJ mice were orally sensitized weekly with casein, using cholera toxin as an adjuvant. Mice were fed with the control or OS (1,8% fructo (long chain) and galacto-OS (9:1) and 0.2% acidic OS) diet, starting two weeks prior to the first sensitization. Regulatory T cells were depleted using αCD25 (PC61, 200 μg, i.p.) before the first and third sensitization. Mice were challenged intra dermally (ear) and orally. The allergic skin reaction was determined by measuring ear swelling (after 1 h) and serum immunoglobulins were measured. In the casein sensitized mice the acute allergic skin reaction was significantly reduced in the OS group (110±11.9 vs 55.7±2.2 μm; p