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Defects in early B‐cell development: comparing the consequences of abnormalities in pre‐BCR signaling in the human and the mouse
Author(s) -
Conley Mary Ellen,
Rohrer Jurg,
Rapalus Lisa,
Boylin Elizabeth C.,
Minegishi Yoshiyuki
Publication year - 2000
Publication title -
immunological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.839
H-Index - 223
eISSN - 1600-065X
pISSN - 0105-2896
DOI - 10.1034/j.1600-065x.2000.17809.x
Subject(s) - bruton's tyrosine kinase , breakpoint cluster region , biology , b cell , phenotype , antibody , cell , gene , b cell receptor , tyrosine kinase , signal transduction , genetics , microbiology and biotechnology , immunology , cancer research
Patients with genetic defects in B-cell development provide an unusual opportunity to dissect the requirements for normal B-cell maturation. It is striking that all of the known genetic defects that result in a failure of B-cell development involve signaling through the pre-B-cell receptor (pre-BCR). Approximately 85% of affected patients are males with mutations in the X chromosome-encoded cytoplasmic tyrosine kinase Btk. Preliminary experiments using stem cell transplants and retroviral-mediated gene therapy in Btk-deficient mice suggest that it may be relatively easy to correct serum immunoglobulins but harder to correct antibody production to T-cell-independent antigens in this disorder. About 3-6% of patients with defects in B-cell development have deletions or critical base pair substitutions in the mu constant region gene. Patients with defects in Igalpha, lambda5 and B-cell linker protein (BLNK) have also been described. All of these patients have a block at the pro-B to pre-B-cell transition. Defects in Btk, lambda5 and BLNK result in a more severe phenotype in the human compared to the mouse. These findings suggest that requirements for signaling through the pre-BCR are more stringent in the human compared to the mouse. Possible explanations for this observation are discussed.