Comparative analysis of the repertoire of insulin-reactive B cells in type 1 diabetes-prone and resistant mice

Molecular characterization and complexity of the immunoglobulin repertoire in the silver-black fox (Vulpes vulpes)

Immunoglobulins, a class of globulins with antibody properties, play a crucial role in the body's defense against pathogens. In this study, we analyzed the gene loci structure of Silver-black fox using a comparative genomics approach. The mechanisms of expression diversity and its preferences were investigated through Next-generation sequencing (NGS). The results revealed 32 potentially functional VH genes, 9 Vκ genes, 17 Vλ genes, 9 DH genes, 3 JH genes, 6 Jκ genes, and 11 Jλ genes, located on different scaffolds. Subsequently, 5'RACE and PE300 bipartite sequencing were used to obtain the reads of the expressed antibody repertoire of Silver-black foxes gene rearrangement events. The analysis indicated a strong preference in the use of V genes, DH genes and J genes by Silver-black fox. The main ways of expression diversity were V(D)J recombination and somatic hypermutation (SHM). The hypermutated region of SHM was not only concentrated in the CDR region but also had higher mutation rate in the FR region. The main types of SHM were G > A, C > T, T > C, and A > G. The findings of this study could serve as a theoretical foundation for a deeper understanding of Silver-black fox immunoglobulins, which is significant for enriching knowledge in immunogenetics and providing theoretical support for future studies on vaccine design for the Silver-black fox.

The role of B cells in the pathogenesis of type 1 diabetes

Type 1 diabetes (T1D) is a metabolic disorder caused by a complete lack of insulin, primarily manifested by hyperglycemia. The mechanisms underlying the onset of T1D are complex, involving genetics, environment, and various unknown factors, leading to the infiltration of various immune components into the islets. Besides T cells, B cells are now considered important contributors to the pathogenesis of T1D, according to recent studies. In non-obese diabetic (NOD) mice, the absence of B cells prevents the development of T1D, and B-cell depletion can even restore the function of pancreatic β cells, emphasizing their involvement in the development of T1D. Naturally, besides pathogenic B cells, regulatory B cells (Bregs) might have a protective function in T1D. This article examines the mechanisms behind B-cell tolerance and the defects in B-cell tolerance checkpoints in T1D. We explored possible functions of B cells in T1D, including the role of islet autoantibodies in T1D, T-B cell interactions, and the role of Bregs in the pathogenesis of T1D. We also summarized the advances of B cell-targeted therapy, exploring new methods for intervention and treatment of T1D.

Factors Governing B Cell Recognition of Autoantigen and Function in Type 1 Diabetes

Islet autoantibodies predict type 1 diabetes (T1D) but can be transient in murine and human T1D and are not thought to be directly pathogenic. Rather, these autoantibodies signal B cell activity as antigen-presenting cells (APCs) that present islet autoantigen to diabetogenic T cells to promote T1D pathogenesis. Disrupting B cell APC function prevents T1D in mouse models and has shown promise in clinical trials. Autoantigen-specific B cells thus hold potential as sophisticated T1D biomarkers and therapeutic targets. B cell receptor (BCR) somatic hypermutation is a mechanism by which B cells increase affinity for islet autoantigen. High-affinity B and T cell responses are selected in protective immune responses, but immune tolerance mechanisms are known to censor highly autoreactive clones in autoimmunity, including T1D. Thus, different selection rules often apply to autoimmune disease settings (as opposed to protective host immunity), where different autoantigen affinity ceilings are tolerated based on variations in host genetics and environment. This review will explore what is currently known regarding B cell signaling, selection, and interaction with T cells to promote T1D pathogenesis.