Immunological activity of chitin and its derivatives.

The effect of chitin and its derivatives on the activation of peritoneal macrophages in vivo, on the suppression of tumour growth in syngeneic mice and on the protection of the host against bacterial infection was examined. Thirty percent deacetylated chitin (30% DA-chitin), 70% DA-chitin and carboxymethyl-chitin (CM-chitin) induced cytotoxic macrophages most effectively. Chitosan, hydroxyethyl-chitin, dihydroxypropyl-chitin (DHP-chitin) and DHP-chitosan had moderate activities. Phosphorylated-, sulphonated- or acetyl-chitin, however, were less effective. Both 70% DA-chitin and DHP-chitosan were most active on the suppression of Meth-A tumour growth in BALB/c mice, and 30% DA-chitin had a moderate effect. For the stimulation of non-specific host resistance against Escherichia coli infection, 30% and 70% DA-chitin were effective.