PLP (139-151) is amino acid residue 139 to 151 of myelin proteolipid protein (PLP) used to induce experimental autoimmune encephalomyelitis (EAE). In Vitro: Severe clinical and histological EAE could be induced by adoptive transfer of the peptide-specific T cell line and 3 of 4 T cell clones. The T cell line/clones all responded strongly to PLP (139-151) in in vitro proliferative assays. Line SPL and all of the clones show strong proliferative response to the whole PLP molecule and to PLP (139-151)^[1]. In Vivo: PLP (139-151) induces acute experimental allergic encephalomyelitis (EAE) in SJL/J mice. Beginning on Day 9, the mice treated with PLP (139-151) show signs of EAE and the disease progressed rapidly to paralysis. Central nervous system inflammation, edema, gliosis, and demyelination are found in all mice killed between Days 10 and 28^[2]. Young male SJL mice immunized with a major encephalitogenic peptide of myelin, PLP 139-151, develop initial clinical and histological symptoms of EAE with a severity similar to age-matched females; however, unlike females, male mice does not relapse. Significant T cell proliferation to PLP 139-151, but not to other PLP and myelin basic protein (MBP) epitopes, is observed in both males and females during the initial episode, recovery, and first relapse of clinical disease^[3].