Anti-idiotypic antibodies against human insulin autoantibodies (IAA)

Abstract

This chapter presents a study that aims to investigate the specificity of the idiotopes expressed by insulin autoantibodies (IAAs) using monoclonal antibodies and to follow up their distribution among patients with insulin dependent diabetes mellitus (IDDM) as well as healthy donors. IAAs in IDDM patients are thought to be associated with the immune attack against the pancreatic beta cells. In this study, blood sera from IDDM patients before the start of insulin therapy and healthy donors were collected and an enzyme-linked immunosorbent assay was used to detect autoantibodies against insulin in tested sera samples. IAAs purified from positive samples were used for production of polyclonal anti-idiotypic antisera and production of hybridomas secreting anti-Id monoclonal antibodies. Data from these experiments show that IAAs express different epitopes recognized by specific monoclonal antibodies (mAbs). Some of the mAbs react with a number of unrelated autoantigens such as dsDNA, insulin, and crystalline, and therefore, can be classified as polyreactive antibodies. Contrary to that, some mAbs seemed to react with the specific antigen used for immunization only, and these antibodies were used to follow up the distribution of the corresponding epitopes among the group of IAA+ sera from diabetics.