Rapid purification of human complement receptor type 1 (CD35, CR1)

We established a rapid purification procedure for complement receptor type 1 (CR1, CD35), Human erythrocyte stromata were solubilized, and the extract was directly applied to a Red-Sepharose column. The eluate was diluted 2-fold, then subjected to an immunoaffinity column, anti-CR1 (named 31R)-conjugated to Sepharose. More than 50% of CR1 was recovered with purity of > 90%, The CR1 preparation showed sufficient cofactor activity for factor I as compared to that prepared by the conventional method. Since 31R recognizes a single epitope in CR1 including its rare variants and soluble forms, this method will allow us to recover with high efficiency these forms of CR1 which have been detected especially in some disease states.