Core Viewpoint - The article discusses a novel therapeutic approach targeting pathogenic T cells in autoimmune diseases, focusing on the mechanism of LAG-3 and T Cell Receptor (TCR) interaction, which offers a new strategy for treatment [4][10]. Group 1: Mechanism of Action - Autoimmune diseases are caused by overactive immune responses leading to tissue damage, with T cells playing a crucial role in diseases like type 1 diabetes and rheumatoid arthritis [2][3]. - LAG-3, an inhibitory immune checkpoint receptor, is regulated by its classical ligand MHC-II, and its activation is dependent on the spatial proximity to TCR, which is essential for effective suppression of CD4+ T cells [4][5][7]. - The study reveals that LAG-3's optimal function requires not just interaction with MHC-II but also the formation of a spatial proximity with TCR, which is a key molecular mechanism for T cell inhibition [7][8]. Group 2: Therapeutic Development - The research team developed a bispecific T cell silencer (BiTS) that targets the interaction between LAG-3 and TCR, allowing for selective modulation of pathogenic T cells while preserving beneficial T cell functions [5][10]. - This innovative approach has shown significant therapeutic effects in various animal models of autoimmune diseases, indicating its potential for treating conditions like refractory multiple sclerosis and rheumatoid arthritis [5][10]. - The study provides a unique opportunity for precise intervention in T cell-driven autoimmune diseases, addressing the current lack of safe and effective therapies [10].