Transepithelial Migration of Leukocytes in the Mammary Gland of Lactating Rats

Open Access
Publisher Website
Google Scholar
Abstract
Cells with morphological characteristics of intraepithelial leukocytes in the mammary alveolar epithelium of lactating rats were described with special reference to their presence in and migration through the epithelium to become normal components of mature milk. These cells, typically located in the basal portion of the alveolar epithelium and intervening between adjacent epithelial cells, were usually observed in the vicinity of myoepithelial cells. Often, they possessed pseudopodia oriented in the direction of the alveolar lumen; however, their extension into this compartment appeared to be inhibited by the apical junctional complexes between adjacent epithelial cells. In certain areas, a complete loss of apical junctional complexes was observed and the resulting epithelial gaps were filled with alveolar secretions in direct contact with an expanse of nude basal lamina. Indeed, the basal lamina appeared to prevent the secretions from entering the extra-alveolar connective tissue as alveolar secretions were never seen in this compartment. Of major interest was the finding that leukocytes were observed both within the epithelial gaps and in the efferent ductal system of the mammary gland. These morphological observations suggest a possible pathway for the migration of leukocytes from the extra-alveolar connective tissue into the exosecretions of the mammary glands, there to be passed to the immunologically naive suckling infant.

This publication has 4 references indexed in Scilit: