EPITOPE SPECIFICITY OF MONOCLONAL AND POLYCLONAL ANTIBODIES TO HUMAN ELASTIN

Polyclonal (pAb) and monoclonal (mAb) anti-human aorta elastin antibod ies were reacted with a series of overlapping hexapeptides along the h uman tropoelastin sequence covering exons 2-7 and 23-36 from the N-ter minus to the C-terminus, advancing 1 amino acid residue each time. ELI SA indicated reactive epitopes. mAb A2.1 recognized sequences containi ng Ala-Lys, mAb G8.1, A7.1 and pAb, hydrophobic sequences. None of the m reacted with the hexapeptide VGVAPG, or with desmosine or isodesmosi ne. pAb L85 reacted with a His-containing sequence coded in exon 26A. pAb kappa E(L), kappa E(S) and L85 reacted with the Cys-containing seq uence of exon 36. A synthetic 14-residue peptide containing the three proximal tyrosines coded in exon 13 did not react with any of the anti sera tested. It appears therefore that the most frequently recognized epitopes are hydrophobic sequences. One polyclonal antibody detected s everal isoforms of tropoelastin in the medium of cultured vascular smo oth muscle cells. Monoclonal and polyclonal antibodies stained elastic fibers on tissue sections, suggesting that the epitopes recognized ar e available on the native fibers for reaction with the antibodies.