Abstract: Cyclosporin A reacted with 4-benzoylbenzoic acid under ultraviolet radiation to give the conjugate of CsABBa. Then, the conjugate was linked to poly-L-lysine with the action of l-ethyl-3-(3-dimethylamino propyl)-carbodiimide hydrochloride to generate CsA immunogen. There were 13.1-17.4 molecules of CsA on each molecule of PL whose average molecular weight was 40 000. The coupling efficiency was fairly high and the constitution of CsA was maintained well.

Key words: Cyclosporin A, Cyclosporin A, Immunogen, Immunogen, 4-Benzoylbenzoic acid, 4-Benzoylbenzoic acid, Polylysine, Polylysine