Quantitative tracing of mRNAs for T- and B-lymphocyte receptor genes in
individual cells by in situ hybridization with fluorochrome-labeled gene
probes. I. Expression in malignancies carrying B-lineage associated
antigens
P Mar, K Pachmann, K Reinecke, B Emmerich and E Thiel
GSF Institut fur Immunologie Munchen, West Germany.
Acute and chronic lymphatic leukemias were investigated on the single- cell
level for the activity of genes coding for the IgM heavy chain and the
alpha and beta chains of the T-cell antigen receptor (TCR). We used a new
method for preparing highly fluorochrome-labeled gene probes for in situ
hybridization, which allowed rapid and quantitative detection of mRNA at
the individual cell level. Leukemic cell populations classified as
belonging to the B lineage according to their surface antigenic patterns
revealed increasing expression of mRNA for the IgM heavy chain (mu mRNA) in
a maturation-dependent fashion, which was not correlated to rearrangement
of the immunoglobulin mu chain gene--only 66% of the leukemias with
rearranged mu gene also transcribed it. TCR mRNA was detected in B-antigen
positive leukemic cells. High levels of both TCR and mu mRNA expression in
all cells of some of these leukemias allowed the conclusion that these
cells simultaneously transcribed the genes for T and B cell antigen
receptors. TCR mRNA was also found in what are considered relatively mature
B leukemias, lineage cross-over on the mRNA level being observed at a
frequency of 23% (five of 22 cases), comparable with that of
"inappropriate" receptor gene rearrangement. The quantitation of mRNA with
fluorochrome-labeled gene probes in situ may allow determining the degree
of gene activation in individual antigenically defined cells and may thus
contribute a new tool for characterization of normal and malignant cells.
Volume 74,
Issue 2,
pp. 638-644,
08/01/1989
Copyright © 1989 by The American Society of Hematology
