ACTIVATION OF THE COMPLEMENT-SYSTEM BY POLYSACCHARIDIC SURFACES BEARING CARBOXYMETHYL, CARBOXYMETHYLBENZYLAMIDE AND CARBOXYMETHYLBENZYLAMIDE SULFONATE GROUPS

Substituted Sephadex (R) derivatives bearing carboxymethyl (CM), CM-be nzylamide (CMB), CM-propylamide (CMP) and CMB-sulphonate (CMBS) groups are used as models of polysaccharidic surfaces to measure the effects of substituting OH groups on the complement activating capacity (CAC) of the modified surfaces in normal human serum. CM substitution decre ases and can suppress the CAC of Sephadex. Low CMB substitution also d ecreases the CAC, whereas high CMB or CMP substitutions increase it ag ain after a minimum. In addition to C3 cleavage occurring at high subs titution with CMB or CMP groups, the presence of CMB induces consumpti on of a protein, limiting CH50 measurements. The CAC variations could be due to rearrangements of the polymer surfaces at the aqueous interf ace with proteins. Highly substituted CMB-bearing surfaces could activ ate complement-like polystyrene surfaces. The presence of CMBS groups does not reduce the CAC of the surface. Such polymer surfaces, which a re heparin-like concerning coagulation, are not heparin-like concernin g complement inhibition.