Mitogen induced activation, proliferation and surface antigen expression patterns in unmutated and hypermutated chronic lymphocytic leukemia cells.
OBJECTIVE
To determine whether the immunoglobulin V(H) gene mutational status has an effect on the activation, proliferation and surface antigen expression of chronic lymphocytic leukemia (CLL) cells when stimulated in vitro.


METHODS
The proliferation and activation responses of CLL cells were studied in 22-immunoglobulin gene V(H) unmutated (UM-CLL) and 12 hypermutated (M-CLL) CLL cases in 4-day cultures. As the mitogen responses have been previously shown to be diverse in CLL, a case-specific strategy based on optimized mitogen combinations (OMCs) of interleukin-2 (IL-2), 12-O-tetradecanoylphorbol 13-acetate (TPA), Staphylococcus aureus Cowan 1 (SAC), and human recombinant tumor necrosis factor alpha (TNF) was applied in cell stimulation. The expression of 23 surface membrane antigens (CD5, CD11c, CD19, CD20, CD21, CD22, CD23, CD25, CD27, CD38, CD40, CD45, CD45RA, CD45RO, CD79b, CD80, CD95, CD124, CD126, CD130, FMC7, IgD, and IgM) was studied by flow cytometry at days 0 and 4.


RESULTS
The proliferation and activation responses were similar in UM-CLL and M-CLL when OMCs contained IL-2, TPA or TNF. SAC induced faster proliferation in UM-CLL than in M-CLL. OMC stimulation induced preferential down-regulation of growth- promoting cell surface receptors CD5, CD21, and CD124 and preferential up-regulation of growth-inhibiting antigen CD80 in M-CLL.


CONCLUSIONS
Difference in immunophenotypic evolution of UM-CLL and M-CLL can be demonstrated if appropriate matrix signals are provided. The pathways for CD5, CD21, CD124 (IL4R), and CD80 (B7-1) regulation should be further explored in relation with somatic hypermutation and outcome of CLL.
Vilpo
Juhani
J
Department of Clinical Chemistry, University of Tampere Medical School and Laboratory Center of Tampere University Hospital, Tampere, Finland. medivil@kolumbus.fi
Tobin
Gerard
G
Hulkkonen
Janne
J
Hurme
Mikko
M
Thunberg
Ulf
U
Sundström
Christer
C
Vilpo
Leena
L
Rosenquist
Richard
R
D015703:Antigens, CD / Q000096:biosynthesis*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D015322:Gene Rearrangement, B-Lymphocyte / Q000187:drug effects / Q000235:genetics; D006801:Humans; D007072:Immunoglobulin D / Q000096:biosynthesis / Q000235:genetics; D007075:Immunoglobulin M / Q000096:biosynthesis; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008934:Mitogens / Q000493:pharmacokinetics*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D027041:Somatic Hypermutation, Immunoglobulin / Q000187:drug effects / Q000235:genetics
D015703:Antigens, CD; D007072:Immunoglobulin D; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D008934:Mitogens