ANTIGENIC STRUCTURE OF PROLINE-RICH REGION-536-566 OF PERTACTIN (P.69) FROM BORDETELLA-PERTUSSIS .2. ANALYSIS OF PEPTIDE-SPECIFIC ANTIBODIES

A new, nonradioactive method for analysis of sub-populations of peptid e-specific polyclonal antibodies (Ab) not requiring their preliminary isolation was developed, B-epitopes recognized by rabbit antibodies in synthetic peptides KAPPAPKPAPQPGPQPP (17P), QPPQPQPEAPAPQP (14P), and GPQPPQPPQP (10P) from proline-rich region 536-566 of Bordetella pertu ssis pertactin were analyzed, Antigenic structure was studied by indir ect and competitive ELISA, immunoaffinity chromatography, isoelectric focusing, and immunoblotting. Antibodies against all three peptides re cognized native pertactin, The anti-14P antibodies recognized an antig enic determinant in the region QPEPAPQP and comprised two major sub-po pulations of antibodies. The anti-10P antibodies interacted with two o verlapping B-epitopes, GPQPPQPPQP and QPPQP. The anti-17P antibodies r ecognized one epitope in the region KAPPAPKPAPQ and two additional ove rlapping antigenic determinants, PGPQPP and PQPP. The minimal sequence recognized by the antibodies against 17P was PQPP, but not QPP. The a nti-17P antibodies comprised approximately 20 main sub-populations, si x or seven of which efficiently interacted with the C-terminal region PGPQPP (6P).