T-cell receptor recognition of Glatiramer Acetate-Major Histocompatibility Complex (TCR-GA-MHC) (TCR-GA-MHC)

The T-cell receptor recognition of the Glatiramer Acetate-Major Histocompatibility Complex (TCR-GA-MHC) is a fundamental immunological interaction targeted in the treatment of relapsing-remitting multiple sclerosis (RRMS) (Arnon & Sela, 2003). Glatiramer acetate (GA) is a random polymer of four amino acids that mimics myelin basic protein (MBP) and binds with high affinity to MHC class II molecules, specifically HLA-DR, on antigen-presenting cells (Neuhaus et al., 2001). This binding serves two primary functions: it competitively displaces myelin autoantigens from the MHC groove and presents a decoy signal to T-cell receptors (TCRs) (Schrempf & Ziemssen, 2007). Recognition of the GA-MHC complex by TCRs promotes the differentiation of GA-specific, anti-inflammatory Th2 and Th3 cells instead of pro-inflammatory Th1 cells (Aharoni et al., 1997). These regulatory T cells migrate to the central nervous system, where they encounter myelin antigens and release suppressive cytokines, a process known as bystander suppression (Ziemssen & Schrempf, 2007). Consequently, this interaction reduces neuroinflammation and the formation of new demyelinating lesions as seen on MRI (FDA, 2014).

Other names

Glatiramer acetate-MHC-TCR interactionCopolymer 1-MHC-TCR interactionGA-HLA-DR-TCR complexT-cell receptor-Glatiramer acetate-MHC class II complex

Glatiramer acetate acts as an altered peptide ligand that competes with myelin basic protein (MBP) for binding to MHC class II molecules (HLA-DR), subsequently modulating T-cell receptor (TCR) signaling to favor anti-inflammatory Th2/Th3 responses over pro-inflammatory Th1 responses, leading to bystander suppression in the CNS (Neuhaus et al., 2001; Arnon & Sela, 2003).