Intraepithelial leukocytes in the Myotis myotis mammary gland.

The morphological and ultrastructural characteristics of intraepithelial leukocytes in the alveolar epithelium of the mammary gland were described in female bats during late pregnancy and lactation. Intraepithelial lymphocytes were principally located in the basal portion of the alveolar epithelium, intermixed with alveolar epithelial cells. They exhibited a spherical shape, with some cytoplasmic prolongations or pseudopodia in association with adjacent epithelial cells. Some eosinophils were observed in the alveolar epithelium of the Myotis myotis mammary gland during the above mentioned periods. Eosinophils often presented pseudopodia that projected themselves between the epithelial cells. In addition, cells of the lymphoid series were observed in the alveol and ductal lumina, forming an integral part of the secreted material (mammary exosecretion).