Expression of mdr1 and mrp in the normal B-cell homologue of B-cell chronic lymphocytic leukaemia.
B-cell chronic lymphocytic leukaemia (CLL) cells commonly express the multidrug resistance phenotype. The aim of this study was to establish whether the normal homologue in B-cell ontogeny of B-CLL also expressed the multidrug resistance (mdr) phenotype. Human tonsillar lymphocytes were sorted to yield two B-cell subsets based on the expression of CD19, CD5 and CD10. The normal homologue was represented by a population of B cells that was CD19 positive, CD10 negative and weakly expressed CD5. Based upon functional analysis and the detection of mdr1 mRNA by semi-quantitative PCR, these cells expressed the mdr phenotype. In contrast, functional multidrug resistance could not be demonstrated in CD19-positive CD10-positive cells with strong expression of CD5, nor could mdr1 mRNA be found in these cells. MRP was variably expressed in both B-cell subsets with no discernable differences in the pattern of expression. We conclude that normal B cells with a phenotype resembling that of B-CLL cells express the multidrug resistance phenotype.
Wall
D M
DM
Department of Haematology, Austin and Repatriation Medical Centre, Victoria, Australia.
el-Osta
S
S
Tzelepis
D
D
Bertoncello
I
I
Kantharidis
P
P
Chou
S T
ST
Zalcberg
J R
JR
Parkin
J D
JD
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D016175:B-Lymphocyte Subsets; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D015448:Leukemia, B-Cell / Q000378:metabolism*; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D016176:T-Lymphocyte Subsets; D014407:Tumor Cells, Cultured
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D012333:RNA, Messenger; C095122:multidrug resistance protein 3