Loss of Langerhans cells from gingival tissue maintained in organ culture.

Changes occurring in a population of Langerhans cells (LC) were investigated using human gingival epithelium maintained in organ culture. The enzyme adenosine-5'-triphosphatase together with the surface antigens HLA-DR and T6 were used to identify and quantitate these cells. An exponential fall in the expression of each of these markers was seen to occur with increasing incubation time, suggesting that a true loss of these cells is in fact occurring. HLA-DR antigen is shed from LC at a rate significantly greater than that at which LC are lost. A mathematical model which simulates the behaviour of LC within organ culture is presented, and several implications and possible explanations proposed.