[Interactions of mononuclear cells of peripheral blood with islet cells in vitro]

Peripheral blood mononuclear cells from Type I diabetic patients health donors or Wistar rats were cultured with rat islet cells for 18 h. Then TNF content of the medium and basal and stimulated insulin release were determined. Mononuclear cells from both healthy donors and diabetic patients could inhibit the insulin release with no correlation to TNF content. Addition of lipopolysaccharide resulted in a 5-7 times increase of TNF content of the medium followed by a more pronounced inhibition of insulin release. Rat mononuclear cells inhibited the beta-cell function almost completely and initially produced large amounts of TNF. The data indicate that inhibition of insulin release by blood mononuclear cells in vitro does not reflect anti beta-cell specific cellular immunity, involves cytokines and, probably depends upon the initial properties of the cells.