Dialyzable lymphoid extract (DLE) from mice resistant to STZ-induced diabetogenesis can interrupt the progress of diabetes in STZ-treated CD-1 mice

DLE was prepared from the minority of euglycemic CD-1 mice, previously injected with STZ, and was administered to hyperglycemic CD-1 male mice 1, 2 and 3 weeks after completion of multidose STZ. Mice treated with DLE derived from 2 x 10(7) (1X) or 10(8) lymphocyte equivalents (lymph.equ.) were significantly less hyperglycemic than the saline treated controls (P<0.001). The effects of DLE remained evident for more than 10 weeks after the final DLE treatment. Mice treated with DLE prepared from diabetic mice (hg DLE) developed a somewhat more rapid onset of hyperglycemia than the STZ treated control animals, although this effect did not achieve statistical significance (P=0.1). This DLE was absorbed on a rat insulinoma cell line (RIN), which contains interspecies cross-reacting islet antigens, and compared to the unabsorbed DLE. Mice treated with hg DLE preabsorbed on RIN cells, showed a slower onset of hyperglycemia. DLE prepared from euglycemia mice and the RIN-absorbed fraction were equally capable of preventing hyperglycemia (P<0.05). In order to determine whether the DLE effects were genetically restricted, DLE was prepared from BALB/c mice, normally resistant to the diabetogenic effects of multidose STZ, both before and after STZ treatment. STZ primed CD-1 mice treated with 3 weekly doses of 2 x 10(7) lymph. equ. of untreated BALB/c derived DLE, STZ treated BALB/c derived DLE, and STZ treated CD-1 DLE were all less hyperglycemic than the control mice, who received saline (P<0.001). However, mice treated with CD-1 DLE were less hyperglycemic than the mice given BALB/c derived DLE (P<0.05). These effects were relatively long-lived. Mice that were given the >3,500 Dalton fraction of CD-1 DLE were significantly less hyperglycemic than either the control mice or those treated with the <3,500 Dalton fraction of CD-1 DLE (P<0.05). Effects remained evident for more than 3 months after the last dose of DLE. Pancreatic tissue from the mice treated with the >3,500 Dalton fraction of CD-1 derived DLE revealed slightly more islets of a slightly greater size with less surrounding inflammation than either control mice or mice treated with the <3,500 Dalton fraction of DLE.