To recognize the complement activation by chitin and chitosan, various physico-chemical aspects were studied. Complement activation
was determined by change of plasma C3 concentration using single radial immunodiffusion method. Results were as follows: in samples with
homogeneous acetylation (oDAC), C3 concentration was decreased with the increase in the degree of acetylation of oDAC. In oDACs 50 and
42 (water soluble materials), however, C3 was not decreased. In samples with heterogeneous acetylation or deacetylation samples (eDAC),
all samples showed C3 activation even in eDAC 53 (solid material) and have almost same activity on complement activation. C3 activation
was not seen in low molecular weight materials including d-glucosamine. The important factors inducing complement activation by
chitosan-based mucopolysaccharide should be solids. The samples with heterogeneous acetylation (eDACs) had a stable ability on complement
activation than with homogeneous acetylation (oDACs). q2000 Elsevier Science Ltd. All rights reserved