D-PEPTIDES AS IMMUNOGENS AND DIAGNOSTIC REAGENTS

There has been a regain of interest in the immunological applications of peptides assembled partly or totally from D-amino acids. Such pepti des are much more stable to proteolysis than natural L-peptides and th ey have considerable potential as synthetic vaccines and as immunomodu lators in T-cell responses. Retro-inverso, also called retro-all-D or retroenantio, peptide analogues that closely mimic the structure of pr otein antigens are obtained by assembling amino acid residues in the r everse order from that in the parent peptides and replacing L- by D-am ino acids. Retro-all-D peptides corresponding to an immunodominant epi tope oi foot-and-mouth disease virus have been shown to elicit high le vels of neutralizing antibodies in experimental animals. Certain retro -all-D peptide analogues of T-cell epitopes are able to bind to MHC cl ass II molecules and may either lead to T-cell activation or inhibit d eleterious T-cell responses.