Study On The Inlfuence Of Lactoferrin On The Balance Of Th1/Th2Cell

Lactoferrin is an80kDa iron-binding glycoprotein which belongs to the transferrin familypossesses biological and physiological functions. The purpose of our present study includes twoaspects. One of both aims to determine the effects of lactoferrin and its pepsin hydrolysate onTh1/Th2cell balance in peripheral blood of the immunosuppressed animals. The other one aimsto determine the immunoregulatory effect of lactoferrin on Th1/Th2cell balance in peripheralblood of food allergy animals.BALB/c mice were intraperitoneally injected with cyclophosphamide (80mg/kg·bodyweight(BW)) to establish immunosuppressed model. The spleen index, thymus index and serumcytokine levels (IL-4, IL-6, IL-10, IL-12p40, IFN-γ, TGF-β) of this model were consecutivelydetermined. Subsequently, the immunoregulatory effects of lactoferrin and lactoferrinhydrolysate given orally to immunosuppressed mice on the Th1/Th2cell balance were evaluatedat different time-points by detecting serum levels of IFN-γ and IL-4and IFN-γ/IL-4ratio. Theresults showed that the immune status of immunosuppressed mice reached the nadir on Day3and the Th1/Th2cell balance shifted to Th2cell direction.20mg/kg·BW of lactoferrin and2mg/kg·BW of lactoferrin hydrolysate significantly enhanced IFN-γ productions and IFN-γ/IL-4ratios in the first2hours. But IL-4levels were not apparently influenced by lactoferrin(P>0.05),and its hydrolysate just significantly decreased IL-4at3h（P≤0.05）. Therefore, lactoferrinand lactoferrin hydrolysate given orally to immunosuppressed mice can display importantimmunoregulatory effects on Th1/Th2cell balance, and impact more on Th1cells.To establish allergic model, BALB/c mice received sensitization and repeat challenges withovalbumin. After treatments with lactoferrin during preventive treatment and intragastricprovocation periods, the serum levels of IgE, IFN-γ, IL-4, IL-6, IL-10, IL-12p40and TGF-βwere determined at1h after the last treatment. The results showed that the Th1/Th2cell balancein peripheral blood of food allergy model shifted to Th2cell direction.2mg/kg·BW oflactoferrin significantly increased IFN-γ, IL-12p40levels and IFN-γ/IL-4ratio but decreased IgE,IL-4and IL-6levels during intragastric provocation periods, while20mg/kg·BW of lactoferrinsignificantly decreased all these cytokines (IFN-γ: from197.8to162.15ng/L；IL-4: from216.45to148.65ng/L；IL-10: from181.2to151.2ng/L；TGF-β: from221.3to162.15ng/L；IL-12p40: from221.2to186.4pg/L；IL-6: from99.6to88.55ng/L). In addition, lactoferrin significantlydecreased the level of specific IgE and increased IFN-γ/IL-4ratio,20mg/kg·BW of lactoferrinimpacted more on IgE (from4.5to4.0μg/L) but2mg/kg·BW of lactoferrin impacted more onIFN-γ/IL-4ratio(from0.8to1.2). Meanwhile, lactoferrin in preventive treatment significantlydecreased the serum levels of IL-4, IL-6, IL-10, IL-12p40, IFN-γ, TGF-β and IgE but increasedIFN-γ/IL-4ratio, especially20mg/kg·BW of lactoferrin. Therefore, we concluded thatlactoferrin could promote the Th1/Th2cell balance in ovalbumin-induced food allergy mice.