PEPTIDE MOTIF OF A CATTLE MBC CLASS-I MOLECULE

A consensus motif for a bovine major histocompatibility complex (MHC) class I molecule, A20, was derived from parainfluenza type-3 (PI-3) vi rus-infected muscle-derived fibroblast cells and peripheral blood leuk ocytes by extraction of the naturally processed peptides from MHC clas s I molecules by treatment with TFA and peptide sequencing of the comp lex mixture. The results showed that the majority of peptides were 9 a mino acids long with position 2 occupied by lysine and position 9 occu pied by arginine. The arginine at position 9 suggests that cattle, lik e humans, but unlike the mouse have permissive TAP transporter molecul es accepting peptides with positively charged amino acids at their C-t erminus. This is the first report of a MHC ligand motif in cattle.