plp (178-191)

PLP (178-191), an immunodominant encephalitogenic epitope from the proteolipid protein (PLP) fragment spanning amino acids 178 to 191, plays a pivotal role in SJL mice. It initiates disease onset earlier compared to the other major encephalitogenic epitope, PLP (139-151), though both epitopes result in similar incidence, severity, and histologic characteristics.

[Leu144,Arg147]-PLP (139-151) is a mutated fragment of the myelin proteolipid protein (PLP), featuring substitutions of tryptophan to leucine and histidine to arginine at positions 144 and 147, respectively. Immunizing mice with this peptide (50 µg) mixed in complete Freund's adjuvant (CFA) elevates IL-4 levels in the spleen. While it suppresses Th1 cell activation in vitro, it does not do so in vivo; instead, it promotes the development of regulatory T cells. Preimmunization with [Leu144, Arg147]-PLP (139-151) postpones the onset of experimental autoimmune encephalomyelitis (EAE) triggered by encephalitogenic peptides from PLP (178-191), myelin oligodendrocyte glycoprotein (MOG) (92-106), or myelin basic protein (MBP) in mice.