A simple two-step procedure for the purification of plasma C1q from different animal species.

Plasma C1q from human, rat, rabbit, dog and sheep were isolated by a 2-step affinity chromatography procedure. In the first step the method exploits the affinity of C1q for heparin and in the second the interaction between C1q and IgG. The precipitation of C1q by the SO4(2-) groups in agarose gels was used as a means to rapidly monitor the elution of C1q. This interaction was found to be non-species specific and therefore obviates the need for immunochemical and/or haemolytic assays. The isolation procedure is rapid, simple and is not confined to one species. Pure functionally active C1q was obtained from all species in yields of approximately 85-95%.