Influence of physico-chemical properties of chitin and chitosan on complement activation

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).