Preparation of red cells coated with C4 and C3 subcomponents and production of anti-C4d and anti-C3d.

Methods of preparing red cells coated only with C4b, C3b or C3d have previously been described by others; the present observations supply further information about the optimal conditions for preparing such cells and also describe conditions for the operation of cells carrying only C4d. In addition, the preparation of specific anti-C4d and anti-C3d sera is described.