Long-term immune characteristics of cow's milk allergy in a mouse model (141.12)

Abstract

Abstract Specific changes in immune memory underlying the ability to outgrow cow’s milk allergy (CMA) are incompletely understood. We studied the long-term immune characteristics of CMA in an adjuvant-free mouse model we have recently published (Gonipeta et al 2009. J. Dairy Sci. 92:4738-4744). Thus, BALB/c mice were sensitized to cow’s milk whey protein using a transdermal sensitization protocol. Subsequently, exposure to whey protein was withdrawn for 3, 5 or 8 months. Fate of circulating IgE and IgG2a antibodies was monitored. Subsequently, mice were given booster exposures and examined for memory IgE, IgG2a, and spleen cell IL-4 and IFN-γ responses. Following allergen withdrawal, IgE antibody levels began to drop. Whereas, significant memory IgE response to booster exposures was evident after 3 months of allergen withdrawal, a weak or no memory IgE response was noted after 5 or 8 months of allergen withdrawal. Despite booster exposures, spleen cell memory IL-4 responses to whey protein was absent after 3, 5 or 8 months of allergen withdrawal. Milk sensitized mice, upon 8 months of allergen withdrawal, exhibited elevated IFN-γ and IgG2a responses suggesting a shift to a TH1 immune profile. In summary, these data suggest that: (i) upon withdrawal of allergen exposure, whey protein specific memory IgE, and memory IL-4 do not persist for long periods; and (ii) there occurs a shift in immune memory towards elevation of TH1 responses as mice age. Funding: US EPA STAR Grant#R833133