M. Wallenohman et Cak. Borrebaeck, A CELL-SURFACE ANTIGEN (BAL) DEFINED BY A MOUSE MONOCLONAL-ANTIBODY INDUCING APOPTOSIS IN A HUMAN LYMPHOCYTIC-LEUKEMIA CELL-LINE, International journal of cancer, 57(4), 1994, pp. 544-552
The lack of apoptosis or programmed cell death in human tumor cells ha
s been suggested to be one factor allowing uncontrolled growth of neop
lasms. We have developed a mouse monoclonal antibody (MAb) that induce
s programmed cell death in a human acute leukemia cell line (KM-3) of
the pre B-cell type. Stable, antibody-producing hybridomas were produc
ed by fusing mouse myeloma cells to spleen cells from mice immunized w
ith viable KM-3 cells. Incubation of KM-3 cells with the MAb (designat
ed anti-BAL) resulted in growth inhibition and subsequent cell death w
ithin 2-3 days. Anti-BAL required cross-linking with a rabbit anti-mou
se antibody to induce DNA fragmentation typical of apoptosis. Immunobl
otting experiments with anti-BAL identified a 37-kDa protein, apparent
ly different from any previously described apoptosis-related surface a
ntigen. Strongest expression of the antigen was generally found on cel
ls of lymphoid or myeloid origin. However, several other cell types su
ch as fibroblasts and endothelial cells were also stained by anti-BAL
in flow cytometry but less intensively. Despite the apparent presence
of this cell surface-bound 37-kDa antigen on several normal and malign
ant cell lines expressing a more immature phenotype.