Campath (alemtuzumab) is a recombinant DNA-derived humanized monoclonal antibody (Campath (alemtuzumab) -IH) directed against the 21-28 kD cell surface glycoprotein, CD52. Campath (alemtuzumab) -1H is an IgGl kappa antibody with human variable framework and constant regions, and complementarity-determining regions from a murine (rat) monoclonal antibody (Campath (alemtuzumab) -1G). The Campath (alemtuzumab) -1H antibody has an approximate molecular weight of 150 kD. Campath (alemtuzumab) is produced in mammalian cell (Chinese hamster ovary) suspension culture in a medium containing neomycin. Neomycin is not detectable in the final product.