The second strategy, developed mainly over the past decade, consisted of more ambitious forms of immune therapy
not aiming at immunosuppression but at inducing/restoring self-tolerance buy MK-2206 to well-defined β cell antigens. The rationale was based on the well-established notion that antigen delivery depends upon the molecular form of the antigen and its route of inoculation, and may lead either to effective immunization or to immune tolerance. This concept stemmed from pioneering experiments performed by D. W. Dresser in the early 1960s, showing that heterologous immunoglobulins that are immunogenic if administered in aggregated form induce specific unresponsiveness/immune tolerance, or ‘immune paralysis’, if injected intravenously (i.v.) in non-aggregated form . Thus it made sense to use well-defined autoantigens as therapeutic tools to attempt inducing/restoring self-tolerance in T1D. As in many other autoimmune diseases, in T1D various candidate autoantigens have been incriminated as potential triggers and targets of the disease. These include the main β cell hormone proinsulin/insulin itself, glutamic acid decarboxylase (GAD), a β cell-specific protein
phosphatase IA-2, a peptide (p277) of heat shock protein 60 (hsp60), the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), a preferential
target of pathogenic CD8+ T cells, and the most recently characterized zinc transporter this website ZnT8. Targeting some of these antigens has proved successful in NOD mice, as disease was effectively prevented by administration of protein or specific peptide antigens such as pro-insulin, insulin, GAD, the p277 peptide of hsp60 using various routes [i.v., subcutaneous (s.c.), oral, intrathymic, intranasal]. Although highly effective in the experimental setting, the transfer to the clinic of β cell autoantigen-induced strategies was beset by a number of difficulties. Antigens used in patients included insulin or altered insulin peptides, GAD65 and the hsp60 Bumetanide p277 peptide (DiaPep277). Most applications have been via administration of the antigen or peptide alone, and one approach has included the administration of antigen plus adjuvant. Insulin has been the main antigen used clinically. It was readily available for clinical use; experiments in animal models consistently showed effects in preventing diabetes; and several evidences suggested that insulin could be a primary autoantigen in T1D. Insulin has been used as an immunotherapy via s.c., i.v., oral and intranasal routes. Two trials performed after diabetes onset in approximately 100 patients have tested the use of oral insulin at a limited dose range without observing efficacy [21,22].