Function Of The Cholera Toxin B Subunit-insulin B Chain Fusion Protein Expressed By Silkworm Larva

Type 1 diabetes, also named Insulin Dependent Diabetes Mellitus(IDDM),is unquestionably an autoimmune disease, which is regulated by T lymphocytes to make insulin secreted less than need because of the destroy of isletβcells. Oral administration of such self-Ags to animals as insulin and glutamic acid decarboxylase (GAD) could induce oral tolerance to protect against diabetes. It is dectected that oral administration of protein antigens is able to efficiently prevent from diabetes without poisonous side-effect in evidence.The oral administration of the soluble self-Ags can especially induce a bystander suppression which react nonspecifically but reaches a specific reaction. But it doesn't suit for the clinical application for its high-frequency, large-dosage and long-term adm -ministration. CTB as a powerful mucous vector can also reduce the oral dosage. The CTB-based therapeutic strategy has been exetensively developed for preventing and treating autoimmune diseases including type 1 diabetes.Insulin B chain contains the predominant epitope of insulin which is one of the type 1 diabeteic self-Ags and feeding of the B chain can protect against the disease in a manner similar to the whole protein in animals.In this report, in order to study the feeding effect of the fusion protein CTB-insB which produced in an amount of 0.902 mg/ml and rebtained the GM1-ganglioside binging affinity by silkworm/BmNPV expression system, we fed the middle-dose of silkworm larva hemolymph to the NOD mice, which showed that a prominent reduction in pancreatic islet inflammation and a delay in the development of the clinical diabetes. This study demonstrates that silkworm derived CTB-insB fusion produce can used as an ideal oral protein vaccine for suppression of insulitis in NOD mice.