Immune-mediated inflammation in the lumen of the bovine mammary gland.

Two groups of cows were sensitized to ovalbumin (OA) during lactation by a subcutaneous injection of OA either in Freund's complete or incomplet adjuvant; two groups of animals injected with the respective adjuvants only served as controls. Intraluminal infusion of microgram quantities of OA in uninflamed mammary glands elicited inflammation, i.e., release of leukocytes into the milk, only in the animals previously sensitized to OA. This indicates that an antigen-specific inflammatory pathway can be established in the mammary gland by parenteral sensitization. Immune-mediated release of leukocytes into the milk could not be reproduced by infusing complement fixing. OA-anti-OA complexes into the lumen of uninflamed glands of unsensitized cows.