Studies in Complement Splitting with Special Reference to the Activation of Yeast Absorbed and Complement Deficient Guinea Pig Serum

摘要

1. 1. Guinea pig complement was split into two pieces by means of CO2. The hemolysis resulting from a mixture of the two fractions showed a loss of about two-thirds of the complement activity. The results of earlier workers as to the quantitative relationships of the two pieces and the modification of the midpiece when standing in sodium chloride were confirmed. Both midpiece and endpiece were found to be labile at 55°C. for thirty minutes.2. 2. Guinea pig complement was split into three pieces by means of (NH4)2SO4 as described by Browning and Mackie. Our results, although less satisfactory quantitatively, confirmed those of the above workers. In light of the difficulties encountered this difference is probably due to the water supplies used for dialysis.3. 3. Attempts were made to split complement into four pieces by means of CO2 and (NH4)2SO4 as described by Browning and Mackie, but with no success. It is highly probable that the water supply affected these results.4. 4. Guinea pig complement absorbed with yeast was activated by both the midpiece and endpiece from the CO2 fractionation, but more consistently and to a greater extent by the former. Heating of the pieces at 55°C. for thirty minutes reduced their ability to reactivate. The reactivation of the yeast absorbed serum by means of the three pieces from the (NH4)2SO4 splitting shows this function to lie entirely in the pseudoglobulin fraction. It is partially destroyed by heating at 56°C. for thirty minutes, due to its isolated condition.5. 5. Serum from the complement deficient guinea pig was always activated by the endpiece from the CO2 splitting in high dilutions, and by the midpiece frequently, but in lower dilutions. Heating at 55°C. for thirty minutes destroyed the activating ability entirely. The data available indicate that both the pseudoglobulin and the albumin from the (NH4)2SO4 splitting will activate the deficient serum to a small extent, but a mixture of the two is essential for the most satisfactory activation.6. 6. The component removed from complement by the absorption with yeast is not identical with that removed by nature in the complement deficient guinea pig serum, since it is impossible to activate them in an identical manner with the fractions obtained by splitting guinea pig serum with CO2 and (NH4)2SO4.