Evidence for normal thymic export of lymphocytes and an intact RT6^a gene in RT6 deficient diabetes prone BB-rats

Diabetes prone BB-rats develop an insulin-dependent diabetes mellitus between postnatal day 60 and 120 in a high incidence. Moreover, even before onset of the diabetes, these animals are deficient in theRT6⁺ subset of T lineage cells. We here put forward evidence that the export of cells from the thymus is normal in these rats, suggesting a maturational block in the periphery. We show furthermore by Southern blot analysis that diabetes prone BB-rats possess the RT6^a gene which is not grossly altered in comparison to that of diabetes resistant strains.