Antibodies to synthetic peptide fragments of T-cadherin as inhibitors of T-cadherin binding to low density lipoproteins

Potential antigenic determinants of the atypical lipoprotein-binding protei ns T-cadherin (p105) and its precursor (p130) from cells of human smooth mu scles were synthesized by the solid phase method according to the Fmoc-sche me. These corresponded to the 51-61, 140-160, 161-179, 260-271, 340-352, 35 0-352, and 370-385 sequences of p130 and were chosen on the basis of comput er analysis of its antigenic structure. The conjugates of the peptides with horseradish peroxidase were used for the immunization of mice and rabbits. Antisera against the peptides corresponding to the 140-160, 161-179, and 2 60-271 sequences of p105 were shown by immunoblotting to react with p105. w hich we isolated from the vascular cells of smooth muscles and earlier iden tified as T-cadherin. These antisera inhibited the binding of low density l ipoproteins with p105 in a dose-dependent manner. These results confirmed t he identification of the p105 protein as T-cadherin and demonstrated the fu ndamental possibility of studying the interaction of this protein with low density lipoproteins by using antipeptide antibodies that inhibit binding.