EFFECT OF ORAL OR PARENTERAL SENSITIZATION TO COW'S MILK ON MUCOSAL PERMEABILITY IN GUINEA-PIGS

Abstract

The systemic and local immune responses and intestinal barrier function were examined in orally or parenterally milk-sensitized guinea-pigs. Both types of sensitization led to positive passive cutaneous anaphylactic responses and high IgG titers against β-lactoglobulin (β-lg) especially in parenterally immunized animals. In Ussing chambers, sensitized jejunum had higher short-circuit current (Isc) than control jejunum, with and without β-lactoglobulin challenge. The further increase in Isc induced by serosal β-lg treatment was higher in parenterally (23.2 ± 3.4 μA/cm2) than orally (10.9 ± 2.9 μA/cm2) sensitized animals. Barrier function was tested as the intestinal transport and degradation of Horseradish peroxidase (HRP) in the presence and absence of β-lg. There was a five-fold increase in degraded HRP transport in sensitized (39.4 ± 6.6 pmoles/h.cm2) versus control (7.37 ± 2.51 pmoles/h.cm2) animals, with and without (β-lg challenge. Serosally applied β-lg enhanced transport of intact HRP in sensitized but not in control animals. These results indicate that sensitization of guinea pigs to cow's milk permanently increases endocytic and electrogenic activities. The challenge with β-lg induced a further transient rise in Isc and increased intact HRP transport.