A fail-safe mechanism for negative selection of isotype-switched B cell precursors is regulated by the Fas/FasL pathway.
J Exp Med
; 198(10): 1609-19, 2003 Nov 17.
Article
em En
| MEDLINE
| ID: mdl-14623914
ABSTRACT
In B lymphocytes, immunoglobulin (Ig)M receptors drive development and construction of naive repertoire, whereas IgG receptors promote formation of the memory B cell compartment. This isotype switching process requires appropriate B cell activation and T cell help. In the absence of T cell help, activated B cells undergo Fas-mediated apoptosis, a peripheral mechanism contributing to the establishment of self-tolerance. Using Igmicro-deficient microMT mouse model, where B cell development is blocked at pro-B stage, here we show an alternative developmental pathway used by isotype-switched B cell precursors. We find that isotype switching occurs normally in B cell precursors and is T independent. Ongoing isotype switching was found in both normal and microMT B cell development as reflected by detection of IgG1 germline and postswitch transcripts as well as activation-induced cytidine deaminase expression, resulting in the generation of IgG-expressing cells. These isotype-switched B cells are negatively selected by Fas pathway, as blocking the Fas/FasL interaction rescues the development of isotype-switched B cells in vivo and in vitro. Similar to memory B cells, isotype-switched B cells have a marginal zone phenotype. We suggest a novel developmental pathway used by isotype-switched B cell precursors that effectively circumvents peripheral tolerance requirements. This developmental pathway, however, is strictly controlled by Fas/FasL interaction to prevent B cell autoimmunity.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Glicoproteínas de Membrana
/
Linfócitos B
/
Deleção Clonal
/
Receptor fas
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Exp Med
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Israel