Although null mutations in Igalpha have been identified in patients with defects in B cell development, no mutations in Igbeta have been reported. We recently identified a patient with a homozygous amino acid substitution in Igbeta, a glycine to serine at codon 137, adjacent to the cysteine required for the disulfide bond between Igalpha and Igbeta. This patient has a small percentage of surface IgM(dim) B cells in the peripheral circulation (0.08% compared with 5-20% in healthy controls). Using expression vectors in 293T cells or Jurkat T cells, we show that the mutant Igbeta can form disulfide-linked complexes and bring the mu H chain to the cell surface as part of the BCR but is inefficient at both tasks. The results show that minor changes in the ability of the Igalpha/Igbeta complex to bring the BCR to the cell surface have profound effects on B cell development.
Dobbs, A. K., Yang, T., Farmer, D., Kager, L., Parolini, O., Conley, M. E., Cutting edge: a hypomorphic mutation in Igbeta (CD79b) in a patient with immunodeficiency and a leaky defect in B cell development, <<JOURNAL OF IMMUNOLOGY>>, 2007; 179 (4): 2055-2059. [doi:10.4049/jimmunol.179.4.2055] [http://hdl.handle.net/10807/92466]
Cutting edge: a hypomorphic mutation in Igbeta (CD79b) in a patient with immunodeficiency and a leaky defect in B cell development
Parolini, OrnellaPenultimo
;
2007
Abstract
Although null mutations in Igalpha have been identified in patients with defects in B cell development, no mutations in Igbeta have been reported. We recently identified a patient with a homozygous amino acid substitution in Igbeta, a glycine to serine at codon 137, adjacent to the cysteine required for the disulfide bond between Igalpha and Igbeta. This patient has a small percentage of surface IgM(dim) B cells in the peripheral circulation (0.08% compared with 5-20% in healthy controls). Using expression vectors in 293T cells or Jurkat T cells, we show that the mutant Igbeta can form disulfide-linked complexes and bring the mu H chain to the cell surface as part of the BCR but is inefficient at both tasks. The results show that minor changes in the ability of the Igalpha/Igbeta complex to bring the BCR to the cell surface have profound effects on B cell development.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.