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Titolo:
A two-phase model of B-cell activation
Autore:
Baumgarth, N;
Indirizzi:
Stanford Univ, Sch Med, Dept Genet, Beckman Ctr B007, Stanford, CA 94305 USA Stanford Univ Stanford CA USA 94305 kman Ctr B007, Stanford, CA 94305 USA
Titolo Testata:
IMMUNOLOGICAL REVIEWS
, volume: 176, anno: 2000,
pagine: 171 - 180
SICI:
0105-2896(200008)176:<171:ATMOBA>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
INDEPENDENT TYPE-2 ANTIGENS; PRIMARY IMMUNE-RESPONSE; ANTIBODY-FORMING-CELLS; T-DEPENDENT ANTIGEN; NATURAL AUTOANTIBODIES; RESPIRATORY-TRACT; HUMORAL IMMUNITY; INFLUENZA-VIRUS; DENDRITIC CELLS; MARGINAL ZONE;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Baumgarth, N Stanford Univ, Sch Med, Dept Genet, Beckman Ctr B007, Stanford, CA 94305 USA Stanford Univ Stanford CA USA 94305 , Stanford, CA 94305 USA
Citazione:
N. Baumgarth, "A two-phase model of B-cell activation", IMMUNOL REV, 176, 2000, pp. 171-180

Abstract

The current paradigm of lymphocyte activation, the two-signal model, has developed from the premise that recognition of antigen alone is insufficientto stimulate naive B cells, as this could potentially induce autoreactive responses, and that cognate T-B interaction is necessary to induce a full B-cell response. Recent evidence suggests, however, that T-cell-independent B-cell activation is part of the humoral immune response to pathogens, and therefore that antigen alone, or antigen plus signals provided by cells other than T cells, can provide all the necessary signals to induce a B-cell response. Furthermore, the presence of secreted IgM produced either as natural antibodies by CD5(+) B-l cells or as antigen-induced IgM by conventional(B-2) cells was shown to affect the kinetics and magnitude of the IgG response significantly. These data and the observed rapid kinetics of in vivo humoral responses seem at odds with a model that predicts that full B-cell activation and expansion is delayed until sufficient T-cell help is generated. I will therefore argue here that, in response to an infection, initial clonal B-cell expansion and secretion of IgM occurs in a T-cell-independent fashion (phase I) driven by the presence of antigen, and that secreted IgM serves as an autocrine growth Factor at this time. B-cell-T-cell interaction occurs only during phase II of the response, thereby initiating the germinal center reaction, isotype switching and memory B-cell development. Hence, this model provides an explanation of how B-cell responses are induced rapidly in vivo at a time when T-cell help is rare.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 17:06:17