Humanized monoclonal antibody specific to lymphocyte antigens. It is a recombinant DNA-derived humanized monoclonal antibody (Campath-1H) that is directed against the 21-28 kD cell surface glycoprotein,CD52. The Campath-1H antibody is an IgG1 kappa with human variable framework and constant regions, and complementarity-determining regions from a murine (rat) monoclonal antibody (Campath-1G). Campath is produced in mammalian cell (Chinese hamster ovary) suspension culture in a medium containing neomycin.
Campath is used to treat leukemia by exploiting antibody mediated lysis of CD52 presenting cells. The CD52 antigen is a cell surface protein found on essentially all B and T lymphocytes, a majority of monocytes, macrophages and most granulocytes. The CD52 antigen is not present on erythrocytes or hematopoetic stem cells. In leukemia there is an excess of B and T cells, so Campath permits selective reduction of lymphocyte populations.