Characterization of human anti-cytomegalovirus monoclonal antibody as biologics.

Human anti-cytomegalovirus (CMV) monoclonal antibody designated C23 was purified from the culture fluid of hybridoma cells which were generated by cell fusion of human lymphocytes and mouse myeloma cells. The purified C23 was found to be identical to human gammaglobulin (HGG) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under both reducing and non-reducing conditions and in gel filtration chromatography. C23 was not contaminated with either aggregated IgG molecules or mouse immunoglobulin chains. In addition, the formulated C23 preparation showed an anti-complement activity low enough to permit its use as a biologic. A virus neutralization titer of C23 was about 1,000 times higher than the titers of HGG preparations. All the tested CMV strains were susceptible to neutralization by C23 and this neutralization was not affected by addition of either beta 2 microglobulin or fresh human serum. These results suggest that human monoclonal antibody C23 is as safe as conventional HGG preparations which have been used in humans, and much more effective in providing host protection against CMV infection.