The use of anti-D purified from human serum to prevent hemolytic disease of the fetus and newborn due to D is well established. Owing to supply and safety reasons, however, an unlimited and non–plasma-derived source of antibodies for Rhesus prophylaxis is needed.STUDY DESIGN AND METHODS
Recombinant human immunoglobulin G (Ig G)1, Ig G2, Ig G3, Ig G4, Ig A1, and Ig A2 anti-D with the same variable region were expressed in Chinese hamster ovary cells. The effector functions of these antibodies were assessed by an antibody-dependent cell-mediated cytotoxicity (ADCC) assay and a chemiluminescence (CL) method for detection of respiratory burst.RESULTS
In the ADCC assay, Ig G1, Ig G3, and Ig A1 did the best and were as active as a currently used prophylactic polyclonal anti-D. Ig G4 and Ig A2 were moderately active, whereas Ig G2 was not active. In the CL assay, Ig G1 and Ig G3 were active but much less so than a currently used prophylactic polyclonal anti-D. For some effector cell preparations, Ig G4 was active in the CL assay, whereas Ig G2, Ig A1, and Ig A2 were not. A mixture of Ig G1 and Ig G3 showed a synergistic effect in the CL assay and did as well as the prophylactic polyclonal anti-D in ADCC and CL. Mixtures of Ig A1 and either Ig G1 or Ig G3 showed no synergistic effect.CONCLUSION
A mixture of recombinant human Ig G1 and Ig G3 anti-D could be of value in future Rhesus prophylaxis.