Expression of Bruton's tyrosine kinase protein within the B cell lineage.
Defects in the gene encoding Bruton's tyrosine kinase (Btk), normally expressed in B cells, cause X-linked agammaglobulinemia (XLA). The phenotype of XLA is characterized by a lack of circulating B cells and immunoglobulin. It has been suggested that B cell maturation from the pre-B cell stage to more mature stages is dependent on the appropriate expression of this gene. The Btk mRNA is expressed in B cells and myeloid cells, but protein expression in relation to B cell maturation has not been determined. Moreover, expression of the Btk protein has so far only been investigated in human Epstein-Barr virus-transformed B cell lines, and in murine splenocytes and B cell lines. We have developed an antiserum which recognizes the human Btk protein and shown that normal human tonsillar B cells, peripheral blood monocytes and myeloid cells express the protein, whereas tonsil-derived T cells do not. We also show that the protein is present in early and mature human B cell lines, but is absent in terminally differentiated plasma cell lines. Furthermore, expression is reduced or absent in three B lineage cell lines derived from two patients with defined genetic mutations in Btk and suffering from XLA.
Genevier
H C
HC
Cellular Immunology Unit, Institute of Child Health, London.
Hinshelwood
S
S
Gaspar
H B
HB
Rigley
K P
KP
Brown
D
D
Saeland
S
S
Rousset
F
F
Levinsky
R J
RJ
Callard
R E
RE
Kinnon
C
C
D000077329:Agammaglobulinaemia Tyrosine Kinase; D001402:B-Lymphocytes / Q000166:cytology / Q000201:enzymology*; D001483:Base Sequence; D015153:Blotting, Western; D002454:Cell Differentiation; D017931:DNA Primers / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010950:Plasma Cells / Q000201:enzymology; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics
D017931:DNA Primers; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human