Affiliation:
1. Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
Abstract
Abstract
The contribution of B lymphocytes as APCs for CD4+ T cell priming remains controversial, based on findings that B cells cannot provide the requisite ligating and costimulatory signals for naive T cells to be activated. In the current study, we have examined Ag-specific T:B cell collaboration under circumstances in which B cells take up Ag through Ig receptors in vivo. This results in their activation and an ability to effectively stimulate naive CD4+ T cells both in vitro and in vivo. The aim of this work was to establish some of the key molecular interactions, as well as kinetics, between Ag-specific T and B cells that enable this priming to take place. Our approach was to amplify the starting pools of both Ag-specific T and B cell populations in vivo to track directly the events during initial T:B cell collaborations. We show that the induction of optimal levels of T cell priming to a protein Ag requires the involvement of Ag-specific B cells. The interaction that results between Ag-specific T and B cells prevents the down-modulation of B7 costimulatory molecules usually observed in the absence of appropriate T cells. Moreover, this prevention in down-modulation is independent of CD40:CD40 ligand contact. Finally, we present data suggesting that once Ag-specific T and B cells interact, there is a rapid (1–2-h) down-regulation of antigenic complexes on the surface of the B lymphocytes, possibly to prevent them from engaging other T cells in the vicinity and therefore focus the initial interaction.
Publisher
The American Association of Immunologists
Subject
Immunology,Immunology and Allergy
Reference36 articles.
1. Healy, J. I., C. C. Goodnow. 1998. Positive versus negative signaling by lymphocyte antigen receptors. Annu. Rev. Immunol. 16: 645
2. Ashwell, J. D.. 1988. Are B lymphocytes the principal antigen-presenting cells in vivo?. J. Immunol. 140: 3697
3. Levin, D., S. Constant, T. Pasqualini, R. Flavell, K. Bottomly. 1993. Role of dendritic cells in the priming of CD4+ T lymphocytes to peptide antigen in vivo. J. Immunol. 151: 6742
4. Wilson, J. L., A. C. Cunningham, J. A. Kirby. 1995. Alloantigen presentation by B cells: analysis of the requirement for B-cell activation. Immunology 86: 325
5. Lassila, O., S. Vainio, P. Matzinger. 1988. Can B cells turn on virgin T cells?. Nature 334: 253
Cited by
8 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献