MULTIVALENT THIOETHER-PEPTIDE CONJUGATES: B CELL TOLERANCE OF AN ANTI-PEPTIDE IMMUNE RESPONSE.

David S. Jones,* Stephen M. Coutts, Christina A, Gamino, G. Michael Iverson, Matthew D. Linnik, Martine E. Randow, Huong-Thu Ton-Nu, and Edward J. Victoria.

La Jolla Pharmaceutical Company, 6455 Nancy Ridge Drive, San Diego, CA 92121

Antibodies which bind b2-glycoprotein I (b2GPI) are associated with antiphospholipid syndrome. Synthetic peptide mimotopes have been discovered which compete with b2GPI for binding to selected anti-b2GPI. A thiol-containing linker was attached to the N-terminus of two cyclic thioether peptide mimotopes, peptides 1a and 1b. The resulting peptides, with linker attached, were reacted with two different haloacetylated platforms to prepare four tetravalent peptide-platform conjugates to be tested as B cell toleragens. The linker-containing peptides were reacted with maleimide-derivatized keyhole limpet hemocyanin (KLH) to provide peptide­KLH conjugates. Peptides 1a and 1b were also modified by acylation with 3-(4'-hydroxyphenyl)propionic acid N-hydroxysuccinimidyl ester. The resulting hydroxyphenyl peptides were radioiodinated and used to measure anti-peptide antibody levels. The KLH conjugates were used to immunize mice to generate an anti-peptide immune response. The immunized mice were treated with the conjugates or saline solution and boosted with the appropriate peptide­KLH conjugate. Three of the four conjugates suppressed the formation of anti-peptide antibody. The stabilities of the conjugates in mouse serum were measured, and the relative stabilities did not correlate with ability to suppress antibody formation

Published in Bioconjugate Chemistry, 1999, 10, 480-488.