Activator-bound C1 is less susceptible to inactivation by C1 inhibition than is fluid-phase C1

摘要: Parameters that influence the effective interaction of C1 with serum regulatory glycoprotein Inhibitor were investigated. bound to activator particles EAC4 or EA was strikingly less susceptible inactivation by than fluid-phase C1. By using conventional hemolytic assay, concentrations required for inhibition 1000-fold higher those With as (and indicator) particle, 17- 75-fold inhibit vs free These findings suggest that, on binding these particulate immune complexes, domain molecule capable interacting is available when in fluid phase. Alternatively, conformation may be altered EAC4, resulting a lower association constant As assessed classical complement pathway hemolysis, enzymatic activity (both phase and particle-bound) markedly dependent concentration reactants. Incubation at resulted more 10 times amount which occurred same ratio components incubated dilute used assays. have allowed development sensitive rapid assay function.