title: Phenotypic and functional characteristics of CD39highhuman regulatory B cells (Breg).
abstract: CD39 and CD73 are key enzymes in the adenosine (ADO) pathway. ADO modulates pathophysiological responses of immune cells, including B cells. It has recently emerged that a subpopulation of ADO-producing CD39+CD73+B cells has regulatory properties. Here, we define the CD39highsubset of these cells as the major contributor to the regulatory network operated by human B lymphocytes. Peripheral blood B cells were sorted into CD39neg, CD39interand CD39highsubsets. The phenotype, proliferation and IL-10 secretion by these B cells were studied by flow cytometry. 5'-AMP and ADO levels were measured by mass spectrometry. Agonists or antagonists of A1R, A2AR and A3R were used to study ADO-receptor signaling in B cells. Inhibition of effector T-cell (Teff) activation/proliferation by B cells was assessed in co-cultures. Cytokine production was measured by Luminex. Uponin vitroactivation and culture of B cells, the subset of CD39highB cells increased in frequency (p< 0.001). CD39highB cells upregulated CD73 expression, proliferated (approximately 40% of CD39highB cells were Ki-67+and secreted fold-2 higher IL-10 and ADO levels than CD39negor CD39interB cells. CD39highB cells co-cultured with autologous Teff suppressed T-cell activation/proliferation and secreted elevated levels of IL-6 and IL-10. The A1R and A2AR agonists promoted expansion and functions of CD39highB cells. CD39 ectonucleotidase is upregulated in a subset ofin vitro-activated B cells which utilize ADO and IL-10 to suppress Teff functions. Proliferation and functions of these CD39highB cells are regulated by A1R- and A2AR-mediated autocrine signaling.
authors.affiliation: Programa de Pós-Graduação em Ciências Biológicas, Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul , Porto Alegre, RS, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Figueiró
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute , Pittsburgh, PA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Muller
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute , Pittsburgh, PA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Funk
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine , Pittsburgh, PA, USA.
authors.forename: E K
authors.initials: EK
authors.lastname: Jackson
authors.affiliation: Programa de Pós-Graduação em Ciências Biológicas, Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: A M O
authors.initials: AM
authors.lastname: Battastini
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute , Pittsburgh, PA, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Whiteside
keywords: 5′-AMP and adenosine production; Autocrine regulation; CD39 and CD73 expression; T-cell suppression; regulatory B cells (Breg)