Overexpression of Natural Killer T Cells Protects Vα14-Jα281 Transgenic Nonobese Diabetic Mice against Diabetes

Abstract

Progression to destructive insulitis in nonobese diabetic (NOD) mice is linked to the failure of regulatory cells, possibly involving T helper type 2 (Th2) cells. Natural killer (NK) T cells might be involved in diabetes, given their deficiency in NOD mice and the prevention of diabetes by adoptive transfer of α/β double-negative thymocytes. Here, we evaluated the role of NK T cells in diabetes by using transgenic NOD mice expressing the T cell antigen receptor (TCR) α chain Vα14-Jα281 characteristic of NK T cells. Precise identification of NK1.1+ T cells was based on out-cross with congenic NK1.1 NOD mice. All six transgenic lines showed, to various degrees, elevated numbers of NK1.1+ T cells, enhanced production of interleukin (IL)-4, and increased levels of serum immunoglobulin E. Only the transgenic lines with the largest numbers of NK T cells and the most vigorous burst of IL-4 production were protected from diabetes. Transfer and cotransfer experiments with transgenic splenocytes demonstrated that Vα14-Jα281 transgenic NOD mice, although protected from overt diabetes, developed a diabetogenic T cell repertoire, and that NK T cells actively inhibited the pathogenic action of T cells. These results indicate that the number of NK T cells strongly influences the development of diabetes.

NOD mice contain an elevated frequency of iNKT17 cells that exacerbate diabetes

“…One wk after the last injection, the mice were sacrificed, the spleens harvested and the splenocytes from individual mice were cultured with or without 100 ng/mL of aGalCer for three days. IL-4, IL-10, IL-17 and IFN-g levels were measured in the supernatants by ELISA as previously described [6,19]. Data correspond to the mean1SD of four individual mice; similar data were obtained in four independent experiments.…”

“…iNKT cells are reduced in number in diabetes-prone NOD mice [4,5], and increasing the number of iNKT cells by adoptive transfer [6,7] or via the introduction of a Va14-Ja18 transgene, reduces significantly the progression of the disease [6]. A similar protection was observed after specific iNKT cell stimulation with exogenous ligands, a-galactosylceramide (a-GalCer) and its analogues [8][9][10][11].…”

“…Mice C57BL/6J, NOD, Ca À/À NK1.1 NOD, BDC2.5 Ca À/À NOD, Va14 NOD, CD1d pLck Va14 NOD, Va14 Ca À/À NOD mice have already been described [6,13,31]. NK1.1 Va14 Ca À/À NOD were generated for iNKT cell subset transfer experiments.…”

“…To determine whether iNKT17 cells infiltrate the pancreas of NOD mice, we have analyzed pancreatic infiltrates from NOD and Va14 NOD transgenic mice that express iNKT cell characteristic TCRa chain and exhibit a10 fold increased frequency and number of iNKT cells in lymphoid tissues [6] as well as in the pancreas [29]. iNKT17 cells represent 6% of all iNKT cells infiltrating the pancreas in NOD and Va14 NOD mice ( Fig.…”

Cd1d–Glycolipid Tetramers

“…In the mouse, CD1d–α-GalCer tetramers should prove indispensable for monitoring NK T cells in the vast majority of inbred strains where the NK1.1 allele is not expressed. Importantly, the list of NK1.1 − strains to be analyzed with tetramers includes BALB/c (the prototype strain for Th2 responses) and the nonobese diabetic mouse, where a role for NK T cells in the control of autoimmune diabetes has been indirectly established 24 25.…”