Application of microbial vaccines in type 1 diabetes mellitus

Type 1 diabetes mellitus(T1DM)is an autoimmune disease characterized by the destruction of β cells and insulin absolutely deficiency upon antigen-specific T lymphocyte attack. The patients with T1DM need insulin therapy for the whole life. Although the mechanism of T1DM is still unclear now, environmental factors play a critical role in the T1DM development because the incidence of infectious diseases is opposite to that of allergies and autoimmune diseases. So far, a variety of bacteria, parasites, viruses and their composition have been proved functional in the prevention of T1DM in animal models. Therefore, microbial vaccine, if administrated early, can induce immune tolerance and prevent the destruction of pancreatic islet β cells, which is expected to be safe and effective novel approach in treating T1DM. This paper summarizes several types of T1DM microbial vaccine and their potential mechanisms including inactivated vaccine, attenuated vaccine, subunit vaccine, DNA vaccine and living-vector vaccine.