[Effect of aging on the gut-associated lymphoid tissue--comparison of the systemic immune functions]

Immune functions generally decline with aging. However, the onset and the rate of the functional decline may be different in each lymphoid compartments. We studied the effects of aging on the murine Peyer's patch cells, which is a part of gut-associated lymphoid tissue (GALT). Peyer's patch cells of 21-months old aged mice retained a greater capacity to proliferate in the response to mitogens, and non-specific immunoglobulin synthesis in vitro. But Peyer's patch cells of 29-months old aged mice showed a distinct functional defect. So, it is suggested that Peyer's patch cells maintain immune functions until certain point of aging and rapidly lose their functions. It is reasonable that GALT maintains the immune functions until certain point of aging, because GALT is one of the first line of defence mechanism and always contact with many dietary and bacterial antigens.