Glycation of biological macromolecules, due to hyperglycemia, promotes the formation of advanced glycation end products (AGEs). It is accelerated in diabetic patients and is responsible for the pathophysiology and progression of diabetes. Previous reports have shown that amount of AGEs formation and glycation-induced structural damage is higher in hemoglobin (Hb) than other proteins present in blood. In our previous study, we have shown structural changes in Hb by D-ribose which may result into the generation of immunogenic neo-epitopes. Thus, we hypothesized that D-ribose induced structural perturbations in Hb, could result in the formation of neo-epitopes which may provoke an auto-immune response and may also be involved in the immuno-pathogenesis of diabetes type-2 associated complications. Therefore, in the current study, we analyzed the prevalence of autoantibodies in diabetic patient's sera against D-ribose glycated-Hb by direct binding and competitive ELISA. Direct binding ELISA confirmed that autoantibodies in diabetic patients exhibit significantly high binding with D-ribose glycated-Hb as compared to its native form. The antigen binding specificity of these antibodies was also screened by competitive inhibition ELISA. We also used D-glucose glycated-Hb as a positive control to detect the presence of auto-antibodies by direct binding and inhibiton ELISA. We found that D-glucose glycated-Hb binds with T2DM samples but the affinity to binding is lower than D-ribose glycated-Hb. The overall findings of this study suggest the prevalence of circulating autoantibodies against D-ribose glycated-Hb in diabetic patients and thus, the level of these autoantibodies may be used as biomarker for progression of diabetes.
Keywords: D-ribose; glycation; hemoglobin; type-2 diabetes mellitus.
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