BOVINE LACTOFERRIN INDUCES BOTH MUCOSAL AND SYSTEMIC IMMUNE-RESPONSE IN MICE

Lactoferrin (Lf) is a milli iron-binding glycoprotein that plays a rol e in iron transport and acts as both a bacteriostatic and a growth mod ulating agent. The aim of this study was to investigate the nature of immune responses induced by repeated oral administration of bovine mil k Lf in mice. Groups of ten female BALB/c mice were fed daily for 4 we eks with two doses of protein antigen: a low (0.05 mg/g body weight pe r d) or high (1 mg/g body weight per d) dose of Lf, or water as a cont rol. A fourth group was immunized intramuscularly with 0.01 mg Lf in c omplete Freund's adjuvant. Anti-Lf IgA and IgG were detected in the in testinal fluid and serum of mice given Lf. Total immunoglobulins were higher in the intestinal fluid in Lf groups than in the control group. No difference could be detected in the serum. IgA and IgG secretion w as enhanced in Peyer's patches and spleen from Lf-fed mice, in compari son with controls. [H-3]thymidine uptake into Peyer's patch and spleen cells from both control and Lf-fed mice was enhanced by 75 mu g Lf/ml in vitro, but Lf groups had a greater proliferation rate than the con trol group. These findings suggested that Lf could act as an immunosti mulating factor on the mucosal immune system and that activation of th e mucosal immune system is dependent on the ability of Lf to bind to t he intestinal mucosa.