Morphologic and functional characteristics of human intestinal lymphoid cells isolated by a mechanical technique

Abstract

A mechanical method for the isolation of viable human intestinal lymphoid cells is described. An average of 6 × 106 lymphoid cells/g of small intestinal mucosa and 4.9 × 106 lymphoid cells/g of large intestinal mucosa were obtained. Small lymphocytes constituted 80% of the intestinal lymphoid cell population. Nine and one-half percent of the lymphoid cells from the large intestine were macrophages, as assessed by their nonspecific esterase activity. Twenty-two percent of the lymphoid cells from the large intestine contained cytoplasmic immunoglobulin, and 73% of these cells contained cytoplasmic IgA. T-lymphocytes constituted 38% of intestinal lymphoid cells as assessed by their ability to form spontaneous rosettes with sheep erythrocytes. Intestinal lymphoid cells were able to respond to the mitogens PHA-P and concanavalin A and also acted as responding cells in one-way mixed leukocyte cultures. However, these cells differed from their peripheral blood counterparts in that the intestinal lymphoid cells demonstrated their maximal response to phytohemagglutinin-P at 5 days, whereas the response of peripheral blood lymphoid cells was maximal at 3 days. Intestinal lymphoid cells neither responded as well as autologous peripheral blood lymphoid cells to an unrelated donor in one-way mixed leukocyte cultures nor were capable of acting as stimulators of the one-way mixed leukocyte reaction. The isolation of a single cell suspension of lymphoid cells from the human gastrointestinal tract by purely mechanical means will allow the examination of the role of the local mucosal immune response in inflammatory, neoplastic, and allergic disorders.