Large mononuclear Ia-positive veiled cells in Peyer's patches. I. Isolation and characterization in rat, guinea-pig and pig.

The antigen presenting cell system in the skin is extensively studied, and is supposed to consist of Langerhans cells in epidermis and dermis, veiled cells in skin lymph and interdigitating cells in skin lymph nodes. In order to detect whether a similar cell system is present in the gut, we studied Peyer's patch cell suspensions. Mononuclear cells with long actively moving cytoplasmic veils were found in cell suspensions from Peyer's patches of rat, guinea-pig, and pig, and in cell suspensions from small intestinal villi of guinea-pig and pig, but not of rat. These veiled cells are strongly Ia-positive. Because of their Ia positivity, their enzyme cytochemical staining pattern, and their ultrastructure, these cells resemble the antigen presenting cells of the skin, skin lymph and lymph node.