Anna Buermann1, Dorothee Römermann1, Wiebke Baars1, Joachim Hundrieser1, Jürgen Klempnauer1, Reinhard Schwinzer2. 1. Transplant Laboratory, Department of General- Visceral- and Transplantation Surgery, Hannover Medical School, Hannover, Germany. 2. Transplant Laboratory, Department of General- Visceral- and Transplantation Surgery, Hannover Medical School, Hannover, Germany. schwinzer.reinhard@mh-hannover.de.
Abstract
BACKGROUND: The development of donor-reactive antibodies is regarded to be an important barrier limiting long-term outcome of allo- and xenografts. We asked whether enhanced signaling via the co-inhibitory receptor programmed cell death-1 (PD-1; CD279) can downregulate human B-cell activation. METHODS: Proliferation of human purified CD19(+) B cells was induced by in vitro stimulation with CpG oligodeoxynucleotides (CpG-B). To induce antibody production, peripheral blood mononuclear cells were co-cultured with the porcine B-cell line L23. Triggering of inhibitory signals via the PD-1 receptor was obtained either using a recombinant agonistic soluble ligand (PD-L1.Ig) or L23 transfectants overexpressing membrane-bound human PD-L1 (CD274; L23-PD-L1 cells). RESULTS: Stimulation of purified CD19(+) B cells with CpG-B resulted in upregulation of PD-1 and strong proliferation. Addition of PD-L1.Ig significantly reduced B-cell proliferation in a dose-dependent manner. A great proportion (~1%) of human circulating B cells recognizes the epitope galactose-α1,3-galactose-β1,4-N-acetylglucosamine-R (α-gal). Thus, when B cells-in the presence of T cell help-were cocultured with α-gal-expressing L23 cells, anti-gal and anti-L23 antibodies could readily be detected in the culture supernatant. The level of induced antibodies was significantly reduced when stimulation was performed by L23-PD-L1 cells. CONCLUSIONS: Enhancing inhibitory signals may be part of future protocols to better control humoral immunity to allo- and xenografts.
BACKGROUND: The development of donor-reactive antibodies is regarded to be an important barrier limiting long-term outcome of allo- and xenografts. We asked whether enhanced signaling via the co-inhibitory receptor programmed cell death-1 (PD-1; CD279) can downregulate human B-cell activation. METHODS: Proliferation of human purified CD19(+) B cells was induced by in vitro stimulation with CpG oligodeoxynucleotides (CpG-B). To induce antibody production, peripheral blood mononuclear cells were co-cultured with the porcine B-cell line L23. Triggering of inhibitory signals via the PD-1 receptor was obtained either using a recombinant agonistic soluble ligand (PD-L1.Ig) or L23 transfectants overexpressing membrane-bound humanPD-L1 (CD274; L23-PD-L1 cells). RESULTS: Stimulation of purified CD19(+) B cells with CpG-B resulted in upregulation of PD-1 and strong proliferation. Addition of PD-L1.Ig significantly reduced B-cell proliferation in a dose-dependent manner. A great proportion (~1%) of human circulating B cells recognizes the epitope galactose-α1,3-galactose-β1,4-N-acetylglucosamine-R (α-gal). Thus, when B cells-in the presence of T cell help-were cocultured with α-gal-expressing L23 cells, anti-gal and anti-L23 antibodies could readily be detected in the culture supernatant. The level of induced antibodies was significantly reduced when stimulation was performed by L23-PD-L1 cells. CONCLUSIONS: Enhancing inhibitory signals may be part of future protocols to better control humoral immunity to allo- and xenografts.
Authors: Samuel Okurut; David B Meya; Freddie Bwanga; Joseph Olobo; Michael A Eller; Fatim Cham-Jallow; Paul R Bohjanen; Harsh Pratap; Brent E Palmer; Katharine H Hullsiek; Yukari C Manabe; David R Boulware; Edward N Janoff Journal: Infect Immun Date: 2020-02-20 Impact factor: 3.441
Authors: Jordi Guiteras; Laura De Ramon; Elena Crespo; Nuria Bolaños; Silvia Barcelo-Batllori; Laura Martinez-Valenzuela; Pere Fontova; Marta Jarque; Alba Torija; Oriol Bestard; David Resina; Josep M Grinyó; Joan Torras Journal: Int J Mol Sci Date: 2021-01-26 Impact factor: 5.923