An alternative B cell development program

Two major types of B cells, the antibody-producing cells of the immune system, are classically distinguished in the spleen: marginal zone (MZ) and follicular (FO). In addition, FO B cells are subdivided into FO I and FO II cells, based on the amount of surface IgM. MZ B cells, which surround the splenic follicles, rapidly produce IgM in response to blood-borne pathogens without T cell help, while T cell-dependent production of high affinity, isotype-switched antibodies is ascribed to FO I cells. The significance of FO II cells and the mechanism underlying B cell fate choices are unclear. We showed that FO II cells express more Sca1 than FO I cells and originate from a distinct B cell development program, marked by high expression of Sca1. MZ B cells can derive from the “canonical” Sca1lo pathways, as well as from the Sca1hi program, although the Sca1hi program shows a stronger MZ bias than the Sca1lo program, and extensive phenotypic plasticity exists between MZ and FO II, but not between MZ and FO I cells. The Sca1hi program is induced by hematopoietic stress and generates B cells with an Igλ-enriched repertoire. In aged mice, the canonical B cell development pathway is impaired, while the Sca1hi program is increased. Furthermore, we showed that a population of unknown function, defined as Lin-c-kit+Sca1+ (LSK-), contains early lymphoid precursors, with primarily B cell potential in vivo. Our data suggest that LSK- cells may represent a distinct precursor for the Sca1hi program in the bone marrow.

Grantor dc:publisher

Alma Mater Studiorum - Università di Bologna

Year dc:date

2008

Author dc:creator

• Fossati, Valentina <1978>

Contributors dc:contributor

• Bagnara, Gian Paolo

• BIO/17 Istologia

Statement dc:rights

• info:eu-repo/semantics/restrictedAccess

Language dc:language

en

Identifier

urn:nbn:it:unibo-669
Fossati, Valentina (2008) An alternative B cell development program, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Biotecnologie dello sviluppo e della riproduzione <https://amsdottorato.unibo.it/view/dottorati/DOT365/>, 20 Ciclo.

OAI identifier oai:identifier

oai:amsdottorato.cib.unibo.it:699