Elimination of carcinoma cells from human bone marrow.

The value of a monoclonal antibody, LICR-LON-Fib-75 (Fib-75), which mediates complement lysis and recognises an antigen present on all epithelial-tumour cells so far studied but not on lymphoid cells or bone-marrow stem cells, in clearing infiltrated bone marrow was assessed. Chromium-51-release and trypan-blue-exclusion assays showed that no tumour cells were viable after exposure to Fib-75 and complement except when large clumps (greater than 500 cells) were present, whereas Fib-75 had no significant effect on bone-marrow cells, as judged by colony-forming-unit and pluripotential-stem-cell assays.