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The non-obese diabetic (NOD) mouse is an animal model of insulin-dependent diabetes mellitus (IDDM), in which 80% of the females become diabetic after the age of 12 weeks. Using an in vitro assay we investigated the capacity of spleen lymphocytes from NOD mice to inhibit the insulin secretion of normal islet cells after stimulation by theophylline plus arginine. Spleen cells from diabetic NOD mice inhibited the insulin release of DBA/2 islet cells. Depletion experiments using monoclonal antibodies demonstrated that inhibitory ceils belonged to the Lyt2 positive T lymphocyte subset. The phenomenon was not restricted by the MHC class I K region, shared by NOD and DBA/2 mice, since lymphocytes from diabetic NOD mice also inhibited the insulin secretion of normal Wistar rat islet cells. Inhibitory T cells were detected in overtly diabetic mice but also in non-diabetic females aged 5-11 weeks indicating that they are not secondary to metabolic disturbances and might contribute to their onset. Conversely they were not found in male NOD mice although some of these mice show insulitis. The presence of these inhibitory T ceils might thus represent an early and sensitive marker of anti-islet cell-mediated autoimmunity. [ABSTRACT FROM AUTHOR]

Mixed lymphocyte cultures were performed before renal transplantation in 36 patients, using the cells from the recipient and the prospective living donor. A highly significant correlation was found between the results of mixed leucocyte cultures and (a) the renal function at one year or two years; (b)the occurrence of early or late rejection crises. A good correlation was also found between the results of mixed cultures and leucocyte typing based on HL-A haplotypes (but not with conventional typing based on the number of antigenic differences). As applied to the selection of the donors for kidney transplantation, the mixed culture has the advantage of recognizing all the 'good' cases, including the favourable cases of the HL-A semi-identical group; it will also select however a small number of poor cases. In contrast, the determination of HL-A haplotypes will select almost only 'good' cases but will discard a significant number of cases which will eventually prove to be favourable. [ABSTRACT FROM AUTHOR]