Summary
Optimal enhancement of hemolytic guinea pig complement activity is obtained at an ionic strength of 0.055.
Reduction of ionic strength permits more efficient conversion of SAC′1a, 4 to SAC′1a, 4,2a which can be traced to firmer binding of C′1a to SA.
The decay rate of SAC′4, 2a is increased at low ionic strength.
The activity of the C′3 complex may be enhanced, unchanged or decreased at low ionic strength, depending on the concentration of SAC′4, 2a and on the nature of the nonelectrolyte used to maintain isotonic conditions.
At low ionic strength, it is possible to lyse sheep erythrocytes in the absence of added hemolytic antibody. Part of this effect has been traced to a dissociable autosensitizer on sheep cells.
Footnotes
A preliminary report of this work was presented at the Complement Workshop held at the National Institutes of Health on March 1, 1963. The nomenclature used here conforms to that found in (1).
