Antibody to folic acid: increased specificity and sensitivity in ELISA by using epsilon-aminocaproic acid modified BSA as the carrier protein.

For raising high titre and specific antibody to haptens or drugs, epsilon-aminocaproic acid modified bovine serum albumin (epsilon-ACA-BSA) was prepared for use as a carrier protein. Folic acid (FA) was coupled to epsilon-ACA-BSA, Imj.BSA and BSA for raising antibodies in rabbits. Enhancement of FA immunogenicity with FA-ACA-BSA was observed. Apart from determination of titre by indirect ELISA, dose-response behaviour and specificity of these antisera were also compared. FA-ACA-BSA antibody showed high sensitivity and specificity. Using this antibody, an ELISA method for the determination of FA was developed. The study provides a simple approach to raise highly specific and high titre antibody against small molecules.