Surface immunoglobulin light-chain expression by the common all cell line REH

To provide further support of the B-cell lineage of common acute lymphoblastic leukemia (ALL), we studied the REH cell line and found not only cytoplasmic heavy chain but also surface lambda light-chain expression by flow cytometry. Nucleic acid blotting experiments on REH revealed that both kappa genes had been deleted and that lambda genes had been rearranged, as expected in B cells expressing lambda light chain. Moreover, REH cells contained mu and lambda RNA. When REH cells were treated with TPA the amount of mu chain RNA increased by approximately fivefold and the amount of lambda chain RNA increased by approximately twofold. The finding of surface immunoglobulin lambda light chain in the REH cell line, suggests that these leukemic cells are further differentiated along the B-cell lineage than was previously believed

Expression of immunoglobulin lambda light chain by the promyelocytic cell line HL-60

The HL-60 cell line, established from a patient with acute promyelocytic leukemia, can be induced to undergo differentiation along the granulocyte or monocyte/macrophage line, depending on the particular inducer that is used. In this communication we provide evidence that HL-60 cells also have B lymphoid characteristics because by flow cytometry and clonal excess calculations, these cells are found to express immunoglobulin (Ig) lambda light chains on their surface. Furthermore, HL-60 cells contain poly(A)+ RNA that hybridizes with a DNA fragment encoding the constant region of Ig lambda chains and comigrates with lambda mRNA on RNA blots. Treatment of HL-60 cells with a phorbol ester that induces monocyte/macrophage differentiation resulted in the loss of surface Ig lambda chains and lambda RNA

Surface immunoglobulin light chain expression in pre-B cell leukemias

Cytofluorographic analysis of surface immunoglobulin (sIg) light chain clonal excess (CE), defined as (%kappa+ - %lambda+)/(%kappa+ + %lambda+) cells per discrete level of fluorescence intensity, was carried out on mononuclear cells of 32 leukemic patients. Eight demonstrated sIg light chain CE, including four blastic chronic myeloid leukemias (BL-CML), three null acute lymphoblastic leukemias (ALL), and one leukemic lymphoblastic lymphoma. Six of the leukemias demonstrated a kappa CE and two had a lambda CE. Sorted kappa+ PB cells from a BL-CML patient were shown to have a diploid DNA stem line and to bear the common ALL antigen. To provide further support for our finding of the expression of sIg light chains in ALL, we studied the REH cell line, derived from a common ALL patient and found cytoplasmic mu heavy chain and surface Ig lambda CE. Nucleic acid blotting experiments on REH revealed that both kappa genes had been deleted and that lambda genes had been rearranged, as expected in B cells expressing lambda light chains. Moreover, REH cells contained mu and lambda RNA. When REH cells were treated with TPA the amount of mu chain RNA increased by approximately fivefold and the amount of lambda chain RNA increased by approximately twofold. The finding of sIg light chain in pre-B cell leukemias and in the REH cell line, suggests that these leukemic cells are further differentiated along the B-cell lineage than was previously believed