Sequence and target receptors of PLP-BPI. PLP-BPI is a linear 33-amino acid peptide, which is composed of the antigenic peptide, PLP139–151 and the ICAM-1 binding peptide, LABL, which is derived from the α-subunit of LFA-1 (CD11a237–246). Both peptides are covalently conjugated to each other via a linker composed of ε-aminocaproic acid and glycine. The N- and C- termini of the peptide are capped by acetylation and amidation, respectively. The hypothesis is that the PLP139–151 portion will bind to MHC-II (I-As) and LABL will simultaneously bind to ICAM-1 on the surface of the APC.