Calcium and Complement Action

Abstract

Dialyzable Ca in serum is not essential for complement action but may be concerned indirectly, due to the equilibrium between dialyzable and non-dialyzable Ca. Non-diffusible Ca appears to be connected in some way with complement activity. The Ca content of various fractions of serum obtained by using CO2 and other acids and the power to reactivate ammonia-inactivated serum shows some correlation. Attempts to reactivate ammonia-treated serum by addition of Ca in various forms were unsuccessful. When complement is split by CO2 all the Ca passes into the albumin fraction. If calcium oleate is added, all the added Ca is found in the albumin fraction. The possibility of chemical separation of complement by dilute acids, if complement consists of Ca soaps, as in Liebermann''s theory, is discussed. Acids which give insoluble Ca salts, such as oxalic and sulphuric, distribute the Ca differently, Ca being found in both fractions, and in the case of oxalic acid mainly in the globulin. The fractions obtained with use of these acids are inactive themselves and the combined fractions have little or no activity. Hydrochloric, acetic and phosphoric acids behave like CO2. No alteration in dialyzable Ca occurs during in-activation by ammonia.