New antibody purification procedure using a thermally responsive poly(N-isopropylacrylamide)-dextran derivative conjugate

Through their specificity and affinity, antibodies are useful tools in rese arch and medicine. In this study, we investigated a new type of chromatogra phic method using a thermosensitive polymer for the purification of antibod ies against a dextran derivative (DD), as a model. The thermally reversible soluble-insoluble poly (N-isopropylacrylamide)-dextran derivative conjugat e, named poly(NIPAAm)-DD, has been synthesized by conjugating amino-termina ted poly(N-isopropylacrylamide) to a DD via ethyl-3-(3-dimethylaminopropyl) -carbodiimide. On one hand, this report describes the two steps of poly(NIP AAm)-DD conjugation and characterization. On the other hand, the poly(NIPAA m)-DD conjugate was used as a tool to purify polyclonal antibodies in serum samples from rabbits subcutaneously immunized with the derivatized dextran . Antibodies were purified and quantified by immunoenzymatic assays. Our re sults indicate that antibodies recognized both DD and poly(NIPAAm)-DD, In c ontrast, they did not bind to native poly(NIPAAm) or poly(NIPAAm) conjugate d with another anionic dextran. We conclude that the conjugation of a polys accharide to poly(NIPAAm) leads to an original and efficient chromatographi c method to purify antibodies. Moreover, this novel method of purification is rapid, sensitive, inexpensive and could be used to purify various types of antibodies. (C) 2001 Elsevier Science B.V. All rights reserved.