The opsonic activity of stored blood

Experiments were performed to measure the stability of opsonins during storage of whole blood collected in CPD solution and stored at 4 C. Three units were collected, and aliquots removed and recalcified on days 0, 3, 7, 14, 21, and 28. Reconstituted serum was immediately frozen and stored at -70 C. The ability to opsonize Escherichia coli 075 and Pseudomonas aeruginosa immunotype 1, both of which require activation and utilization of the alternative pathway of complement for opsonization, were performed simultaneously for each organism and for each unit. Results showed that there was a slight but insignificant reduction in opsonic strength during storage for up to 28 days. The results indicate that standard collection and storage conditions using CPD as the anticoagulant retains functional activity of the alternative pathway. C3 measured by radial immunodiffusion using antisera against the B antigenic determinant showed that C3 had not been converted during storage.