Total hemolytic activities of mouse serum complement. Well 1, quality control. Wells 2 to 8, dilutions of the standard using the manufacturer's standard. Wells 9 to 11, serum from WT mice, showing positive reactions (complement is present). Similar positive reactions were obtained with serum from C3+/+, C5+/+ CR2+/+, and CR2−/− mice (not shown). Wells 12 to 14, serum from C5−/− mice, showing no reaction (complement is absent). Similar negative reactions were obtained with serum from CVF-pretreated WT, C3+/+, and C5+/+ mice (not shown).