Acquired immunogenicity of calf thymus DNA and LDL modified by D-ribose: a comparative study

Glycation of biologically important macromolecules leads to the establishment of advanced glycation end products (AGEs) having significant role in the pathophysiology of various diseases. d-Ribose, is a highly reactive pentose sugar resulting in the rapid formation of AGEs. Formation of d-ribose derived glycated DNA and LDL has been previously demonstrated; however no comparative, extensive studies have been performed to assess the immunogenicity of d-ribose glycated calf thymus DNA (CT-DNA) and LDL. In the present study, the results showed that animals immunized with d-ribose modified CT-DNA and LDL induced antibodies as detected by direct binding and competition ELISA. The modified CT-DNA and LDL were found to be highly immunogenic, eliciting high titer immunogen-specific antibodies, while the native forms of DNA was almost non-immunogenic. The induced antibodies from modified CT-DNA and LDL exhibited wide range of heterogeneity in recognizing various nucleic acid conformers, DNA bases and amino acids. Furthermore, Serum antibodies from diabetes and diabetes atherosclerosis patients were screened for their binding to native CT-DNA, LDL and glycated CT-DNA, LDL. Glycated CT-DNA showed almost equivalent binding to both diabetes and diabetic atherosclerosis group while high recognition was observed when glycated LDL was used as an antigen.