Synthesis of a MDP Analogue/Chitin Conjugate That Stimulates Cultured Macrophages

To provide a new synthetic biological response modifier which ex hibits a high immunopotentiation activity and antitumor activity, a hybrid conjugate of chitin with immobilized D-glucose analogue of muramyl dipeptide (MDP) (GADP) was synthesized. The stimulation activity of the conjugate against cultured macrophages was evaluated as an immunopotentiation activ ity in vitro by glucose consumption using PMA (phorbol-12-myristate-13- acetate)-differentiated HL-60 (human promyelocytic leukemia) cells and by superoxide anion (O ^2- ) production from PMA-differentiated HL-60 cells. The stimulation activity of the GADP/chitin conjugate against cultured macrophages was greater than that of GADP derivative, carboxymethyl-chitin and a mixture of these two. The stimulation activity of GADP against cultured macrophages was increased by conjugation with chitin.