Proinsulin peptide-HLA class II complex (pINS-HLA-II)

The proinsulin peptide-HLA class II complex is a therapeutic target used in antigen-specific immunotherapies for Type 1 Diabetes Mellitus (T1DM) [3, 5]. This complex consists of a proinsulin-derived epitope, such as the C19-A3 peptide, bound to high-risk HLA class II molecules like HLA-DR4 (specifically DRB1*04:01) [9, 15]. In tolerogenic therapies, these complexes are presented on the surface of autologous tolerogenic dendritic cells (tolDCs) that have been modulated ex vivo with agents like Vitamin D3 and dexamethasone to maintain a stable, non-inflammatory state [3, 10]. The complex is recognized by proinsulin-specific T-cell receptors (TCRs) on autoreactive CD4+ T cells [13, 19]. Presentation of the antigen in this tolerogenic context aims to re-educate the immune system by inducing the expansion of antigen-specific regulatory T cells (Tregs) and promoting the anergy or deletion of pathogenic effector T cells [3, 16]. This approach seeks to halt the autoimmune destruction of pancreatic beta cells and preserve endogenous insulin production, as evidenced by clinical trials of vaccines like PIpepTolDC [2, 8].

Other names

Proinsulin peptide-MHC II complexpINS:HLA-DR4 complexC19-A3:HLA-DR4 complexProinsulin-specific T-cell receptor ligandpMHC II complex

Induction of antigen-specific regulatory T cells (Tregs) and suppression of autoreactive effector T cells through presentation of proinsulin epitopes in a tolerogenic context.