Role of Complement in Blood Preservation and Blood Banking.
Final rept. 1 May 79-31 Dec 80,
MASSACHUSETTS UNIV MEDICAL SCHOOL WORCESTER
Pagination or Media Count:
We are describing here in detail a new method to quantitate cell-bound complement in accurate molecular terms. The method is extremely sensitive so that it is possible to quantitate the presence of even ten molecules per cell and it can be utilized to measure complement on various blood cells in-vivo and in-vitro. Utilizing this method we quantitated C3d molecules on fresh RBC and C3b molecules on both stored and quality control RBC EC43. On the average, 94 C3d molecules and zero C3b molecules were detected on fresh RBC. RBC that had been stored at 4 C for 21 days had acquired about 64 C3b molecules per cell. The number of C3b molecules on heavily sensitized EC43 varied between 2700 to 3000. Other investigators, using radioactive antibodies, detected about 550 C3d molecules on fresh RBC and about 200,000 C3b molecules on EC43. These differences in results apparently reflect methodological bias and could be explained the following way Since non-monoclonal antibodies were used, they probably consisted of a mixture of antibodies directed to various epitopes on the antigens molecule so that the ratio between radiolabeled antibody and antigen molecules exceeded one. This would favor high results in the radioactive method. In contrast, our results were not calculated on the basis of antibody-antigen ratio but were compared to particle-bound C3 standard. The new immunochemical method will be applied for quantitation of C3 on various populations of stored RBC to determine whether RBC aged in-vivo are more susceptible to complement-induced storage lesion than young RBC. Author
- Medicine and Medical Research