Leptin does not influence the IgE response to ovalbumin in mice.

Leptin is important for maintenance of the body's energy homeostasis and it also increases Th1 and suppresses Th2 cytokine production. We have investigated the effect of leptin on the allergic immune response to the model allergen ovalbumin (OA) by using the popliteal lymph node assay (PLNA) and serum antibody determination in mice. Mice were injected with either leptin i.v. plus OA in one hind footpad, or leptin or OA alone. A booster dose of leptin was given twice and of OA once and the animals were exsanguinated on experimental day 19 when the PLNs also were removed. End-point measurements were serum levels of IgE, IgG1, and IgG2a anti-OA and weight and cell number of the excised PLNs. Leptin given i.v. with the protocol employed altered neither the cellular PLN response nor the specific serum IgE, IgG1, or IgG2a anti-OA levels compared with the group given OA without leptin. Our data indicate that systemic administration of leptin neither suppresses nor enhances the Th2-dependent antibody responses in the present mouse model.