Fig 3.

Affinity-purified immunoglobulins demonstrate dose-dependent and specific binding to their selecting peptides. Immunoglobulin fractions were obtained from sera from patients 1A76 and 3A64 by affinity purification using peptide I (peptide I-Ig) and peptide II (peptide II-Ig), which correspond to E2 regions encompassing aa 412 to 423 and aa 434 to 446, respectively. Affinity-purified immunoglobulin and monoclonal antibodies AP33 and 2/69a were tested by an immunoassay for reactivity to immobilized peptide I (A) or peptide II (B). ■, 1A76 peptide I-Ig; ●, 3A64 peptide I-Ig; □, 1A76 peptide II-Ig; ○, 3A64 peptide II-Ig; ▲, MAb AP33; △, MAb 2/69a.