EFFECT OF IONIC STRENGTH ON HAEMOLYTIC ACTIVITY OF COMPLEMENT

Abstract

The haemolytic activity of guinea-pig complement has been measured in isotonic solutions of various ionic strengths in the range 0.034[long dash]0.28 and shown to be maximum at an ionic strength close to 0.08. Hasmolytic activity was virtually abolished at ionic strength 0.034, while at 0.28, the complement titre was only about 20 per cent of the value found at the physiological ionic strength 0.155. NaCl KC1, LiBr and K2SO4 were the electrolytes used to provide ionic strength, and sucrose, mannitol and inositol the non-electrolytes used to maintain isotonicity. Nine permutations of the four electrolytes with the three non-electrolytes were tested and gave similar results. Human and rabbit complements also showed optimum haemolytic activity at ionic strength 0.08-0.10.