High expression of 5-lipoxygenase in normal and malignant mantle zone B lymphocytes.
BACKGROUND
Human B lymphocytes can produce leukotriene B4 but the biological function of the 5-lipoxygenase (5-LO) pathway in B cells is unclear. In order to better understand and define the role of 5-LO in B cells, we investigated the expression of 5-LO mRNA and protein in subsets of B cells from human tonsils and different types of B cell lymphoma.


RESULTS
Based on RT-PCR and western blot/immunohistochemical staining, with a polyclonal antibody raised against 5-LO, high expression of 5-LO was found in mantle zone B cells from tonsils. By contrast, only a weak expression of 5-LO was detected in germinal centre cells and no expression in plasma cells from tonsils. This pattern of 5-LO expression was preserved in malignant lymphoma with high expression in mantle B cell lymphoma (MCL) and weak or no expression in follicular lymphoma. Primary leukemized MCL, so called B-prolymphocytic leukaemia cells, and MCL cell lines also expressed 5-LO and readily produced LTB4 after activation.


CONCLUSIONS
The present report demonstrates the expression of 5-LO mainly in normal and malignant mantle zone B cells while the expression is low or absent in germinal centre B cells and plasma cells, indicating a role of the 5-LO pathway in B cells before the cells finally differentiate to plasma cells.
Mahshid
Yilmaz
Y
Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden. yilmaz.mahshid@ki.se
Lisy
Marcus-René
MR
Wang
Xiao
X
Spanbroek
Rainer
R
Flygare
Jenny
J
Christensson
Birger
B
Björkholm
Magnus
M
Sander
Birgitta
B
Habenicht
Andreas J R
AJ
Claesson
Hans-Erik
HE
D001094:Arachidonate 5-Lipoxygenase / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000201:enzymology* / Q000276:immunology; D001402:B-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D015153:Blotting, Western; D002454:Cell Differentiation; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D015971:Gene Expression Regulation, Enzymologic; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D007111:Immunity, Cellular; D007156:Immunologic Memory; D016130:Immunophenotyping; D054403:Leukemia, Prolymphocytic, B-Cell / Q000201:enzymology* / Q000276:immunology; D007975:Leukotriene B4 / Q000378:metabolism; D008213:Lymphocyte Activation; D008224:Lymphoma, Follicular / Q000201:enzymology* / Q000276:immunology; D020522:Lymphoma, Mantle-Cell / Q000201:enzymology* / Q000276:immunology; D008856:Microscopy, Fluorescence; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology; D016133:Polymerase Chain Reaction; D015398:Signal Transduction
D007975:Leukotriene B4; D001094:Arachidonate 5-Lipoxygenase