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Müller-Winkler J, Mitter R, Rappe JCF, Vanes L, Schweighoffer E, Mohammadi H, Wack A, Tybulewicz VLJ. Critical requirement for BCR, BAFF, and BAFFR in memory B cell survival. J Exp Med 2021; 218:211510. [PMID: 33119032 PMCID: PMC7604764 DOI: 10.1084/jem.20191393] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 07/22/2020] [Accepted: 09/14/2020] [Indexed: 01/23/2023] Open
Abstract
Memory B cells (MBCs) are long-lived cells that form a critical part of immunological memory, providing rapid antibody responses to recurring infections. However, very little is known about signals controlling MBC survival. Previous work has shown that antigen is not required for MBC survival, but a requirement for the B cell antigen receptor (BCR) has not been tested. Other studies have shown that, unlike naive B cells, MBCs do not express BAFFR and their survival is independent of BAFF, the ligand for BAFFR. Here, using inducible genetic ablation, we show that survival of MBCs is critically dependent on the BCR and on signaling through the associated CD79A protein. Unexpectedly, we found that MBCs express BAFFR and that their survival requires BAFF and BAFFR; hence, loss of BAFF or BAFFR impairs recall responses. Finally, we show that MBC survival requires IKK2, a kinase that transduces BAFFR signals. Thus, MBC survival is critically dependent on signaling from BCR and BAFFR.
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Xie J, Trus I, Oh D, Kvisgaard LK, Rappe JCF, Ruggli N, Vanderheijden N, Larsen LE, Lefèvre F, Nauwynck HJ. A Triple Amino Acid Substitution at Position 88/94/95 in Glycoprotein GP2a of Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV1) Is Responsible for Adaptation to MARC-145 Cells. Viruses 2019; 11:v11010036. [PMID: 30626009 PMCID: PMC6356402 DOI: 10.3390/v11010036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 02/05/2023] Open
Abstract
The Meat Animal Research Center-145 (MARC-145) cell line has been proven to be valuable for viral attenuation regarding vaccine development and production. Cell-adaptation is necessary for the efficient replication of porcine reproductive and respiratory syndrome virus (PRRSV) in these cells. Multiple sequence analysis revealed consistent amino acid substitutions in GP2a (V88F, M94I, F95L) of MARC-145 cell-adapted strains. To investigate the putative effect of these substitutions, mutations at either position 88, 94, 95, and their combinations were introduced into two PRRSV1 (13V091 and IVI-1173) infectious clones followed by the recovery of viable recombinants. When comparing the replication kinetics in MARC-145 cells, a strongly positive effect on the growth characteristics of the 13V091 strain (+2.1 log10) and the IVI-1173 strain (+1.7 log10) compared to wild-type (WT) virus was only observed upon triple amino acid substitution at positions 88 (V88F), 94 (M94I), and 95 (F95L) of GP2a, suggesting that the triple mutation is a determining factor in PRRSV1 adaptation to MARC-145 cells.
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Affiliation(s)
- Jiexiong Xie
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
| | - Ivan Trus
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
| | - Dayoung Oh
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
| | - Lise K Kvisgaard
- National Veterinary Institute, Technical University of Denmark, 2800 Lyngby, Denmark.
| | - Julie C F Rappe
- The Institute of Virology and Immunology IVI, 3147 Mittelhäusern and Bern, Switzerland.
- Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland.
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland.
| | - Nicolas Ruggli
- The Institute of Virology and Immunology IVI, 3147 Mittelhäusern and Bern, Switzerland.
- Department of Infectious Diseases and Pathobiology, University of Bern, 3012 Bern, Switzerland.
| | - Nathalie Vanderheijden
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
| | - Lars E Larsen
- National Veterinary Institute, Technical University of Denmark, 2800 Lyngby, Denmark.
| | - François Lefèvre
- INRA, Molecular Immunology and Virology Unit, 78350 Jouy-en-Josas, France.
| | - Hans J Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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Rappe JCF, García-Nicolás O, Flückiger F, Thür B, Hofmann MA, Summerfield A, Ruggli N. Heterogeneous antigenic properties of the porcine reproductive and respiratory syndrome virus nucleocapsid. Vet Res 2016; 47:117. [PMID: 27871316 PMCID: PMC5118883 DOI: 10.1186/s13567-016-0399-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/27/2016] [Indexed: 12/21/2022] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus responsible for a widespread contagious disease of domestic pigs with high economic impact. Switzerland is one of the rare PRRSV-free countries in Europe, although sporadic outbreaks have occurred in the past. The PRRSV isolate IVI-1173 from the short outbreak in Switzerland in 2012 was entirely sequenced, and a functional full-length cDNA clone was constructed. Genetic and antigenic characterization of IVI-1173 revealed the importance of amino acid 90 of the nucleocapsid protein N as part of a conformational epitope. IVI-1173 was not detected by SDOW17, a monoclonal antibody against N widely used to detect PRRSV-infected cells. Substitution of alanine at position 90 of N [N(A90)] with a threonine [N(T90)] restored reactivity of vIVI1173-N(T90) to SDOW17 completely. The relevance of this amino acid for the conformational SDOW17 epitope of PRRSV N was further confirmed by the opposite substitution in a functional cDNA clone of the genotype 2 isolate RVB-581. Finally, N proteins from ten genotype 1 strains differing from threonine at position 90 were analysed for reactivity with SDOW17. N(A90) totally disrupted or severely affected the epitope in 7 out of 8 strains tested. Based on these findings, 225 genotype 1 strains were screened for the prevalence of N(A90). N(A90) is rare in classical subtype 1 and in subtype 3 strains, but is frequent in Russian subtype 1 (70%) and in subtype 2 (45%) isolates. In conclusion, this study highlights the variable antigenic properties of N among genotype 1 PRRSV strains.
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Affiliation(s)
- Julie C F Rappe
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | | | - Barbara Thür
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Office for Consumer Protection, Canton Aargau, Obere Vorstadt 14, 5000, Aarau, Switzerland
| | - Martin A Hofmann
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland
| | - Artur Summerfield
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Nicolas Ruggli
- The Institute of Virology and Immunology IVI, Mittelhäusern, Switzerland.
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García-Nicolás O, Auray G, Sautter CA, Rappe JCF, McCullough KC, Ruggli N, Summerfield A. Sensing of Porcine Reproductive and Respiratory Syndrome Virus-Infected Macrophages by Plasmacytoid Dendritic Cells. Front Microbiol 2016; 7:771. [PMID: 27458429 PMCID: PMC4937788 DOI: 10.3389/fmicb.2016.00771] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/06/2016] [Indexed: 11/17/2022] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) represents a macrophage (MØ)-tropic virus which is unable to induce interferon (IFN) type I in its target cells. Nevertheless, infected pigs show a short but prominent systemic IFN alpha (IFN-α) response. A possible explanation for this discrepancy is the ability of plasmacytoid dendritic cells (pDC) to produce IFN-α in response to free PRRSV virions, independent of infection. Here, we show that the highly pathogenic PRRSV genotype 1 strain Lena is unique in not inducing IFN-α production in pDC, contrasting with systemic IFN-α responses found in infected pigs. We also demonstrate efficient pDC stimulation by PRRSV Lena-infected MØ, resulting in a higher IFN-α production than direct stimulation of pDC by PRRSV virions. This response was strain-independent, required integrin-mediated intercellular contact, intact actin filaments in the MØ and was partially inhibited by an inhibitor of neutral sphingomyelinase. Although infected MØ-derived exosomes stimulated pDC, an efficient delivery of the stimulatory component was dependent on a tight contact between pDC and the infected cells. In conclusion, with this mechanism the immune system can efficiently sense PRRSV, resulting in production of considerable quantities of IFN-α. This is adding complexity to the immunopathogenesis of PRRSV infections, as IFN-α should alert the immune system and initiate the induction of adaptive immune responses, a process known to be inefficient during infection of pigs.
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Affiliation(s)
| | - Gaël Auray
- The Institute of Virology and Immunology (IVI) Mittelhäusern, Switzerland
| | - Carmen A Sautter
- The Institute of Virology and Immunology (IVI) Mittelhäusern, Switzerland
| | - Julie C F Rappe
- The Institute of Virology and Immunology (IVI) Mittelhäusern, Switzerland
| | | | - Nicolas Ruggli
- The Institute of Virology and Immunology (IVI) Mittelhäusern, Switzerland
| | - Artur Summerfield
- The Institute of Virology and Immunology (IVI)Mittelhäusern, Switzerland; Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of BernBern, Switzerland
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