Cytotoxic Lymphocytes in Human Intestinal Mucosa
Although cytotoxic lymphocytes have been well studied and characterized in the peripheral blood, the nature and function of these effector cells in human gut mucosa is still unclear. Previous studies have suggested that human intestinal lamina propria lymphocytes (LPL) exhibit mitogen induced cellular cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) but that freshly isolated mucosal cells do not exhibit NK activity or exhibit it at very low levels (1–7). This is surprising since the intestinal mucosa is frequently affected by neoplastic, infectious and inflammatory diseases and is in apparent contrast with studies of the mucosal immune system in rodents where spontaneously cytotoxic cells are well represented (8,9). However, when isolated human colonic cells are cultured in the presence of interleukin-2 (IL-2) significant lytic activity is observed (lymphokine activated killers [LAK]) (10, 11).
KeywordsMucosal Immune System Cytotoxic Lymphocyte Lamina Propria Lymphocyte Human Colonic Cell Lamina Propria Mononuclear Cell
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