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Arbulo-Echevarria MM, Vico-Barranco I, Narbona-Sánchez I, García-Cózar F, Miazek A, Aguado E. Increased Protein Stability and Interleukin-2 Production of a LAT G131D Variant With Possible Implications for T Cell Anergy. Front Cell Dev Biol 2020; 8:561503. [PMID: 33042995 PMCID: PMC7517355 DOI: 10.3389/fcell.2020.561503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/13/2020] [Indexed: 11/13/2022] Open
Abstract
The adaptor LAT plays a crucial role in the transduction of signals coming from the TCR/CD3 complex. Phosphorylation of some of its tyrosines generates recruitment sites for other cytosolic signaling molecules. Tyrosine 132 in human LAT is essential for PLC-γ activation and calcium influx generation. It has been recently reported that a conserved glycine residue preceding tyrosine 132 decreases its phosphorylation kinetics, which constitutes a mechanism for ligand discrimination. Here we confirm that a LAT mutant in which glycine 131 has been substituted by an aspartate (LATG131D) increases phosphorylation of Tyr132, PLC-γ activation and calcium influx generation. Interestingly, the LATG131D mutant has a slower protein turnover while being equally sensitive to Fas-mediated protein cleavage by caspases. Moreover, J.CaM2 cells expressing LATG131D secrete greater amounts of interleukin-2 (IL-2) in response to CD3/CD28 engagement. However, despite this increased IL-2 secretion, J.CaM2 cells expressing the LATG131D mutant are more sensitive to inhibition of IL-2 production by pre-treatment with anti-CD3, which points to a possible role of this residue in the generation of anergy. Our results suggest that the increased kinetics of LAT Tyr132 phosphorylation could contribute to the establishment of T cell anergy, and thus constitutes an earliest known intracellular event responsible for the induction of peripheral tolerance.
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Affiliation(s)
| | | | | | - Francisco García-Cózar
- Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain.,Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Arkadiusz Miazek
- Department of Biochemistry and Molecular Biology, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Enrique Aguado
- Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain.,Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
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2
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Arbulo-Echevarria MM, Narbona-Sánchez I, Fernandez-Ponce CM, Vico-Barranco I, Rueda-Ygueravide MD, Dustin ML, Miazek A, Duran-Ruiz MC, García-Cózar F, Aguado E. A Stretch of Negatively Charged Amino Acids of Linker for Activation of T-Cell Adaptor Has a Dual Role in T-Cell Antigen Receptor Intracellular Signaling. Front Immunol 2018; 9:115. [PMID: 29456532 PMCID: PMC5801411 DOI: 10.3389/fimmu.2018.00115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/15/2018] [Indexed: 11/13/2022] Open
Abstract
The adaptor protein linker for activation of T cells (LAT) has an essential role transducing activatory intracellular signals coming from the TCR/CD3 complex. Previous reports have shown that upon T-cell activation, LAT interacts with the tyrosine kinase Lck, leading to the inhibition of its kinase activity. LAT-Lck interaction seemed to depend on a stretch of negatively charged amino acids in LAT. Here, we have substituted this segment of LAT between amino acids 113 and 126 with a non-charged segment and expressed the mutant LAT (LAT-NIL) in J.CaM2 cells in order to analyze TCR signaling. Substitution of this segment in LAT prevented the activation-induced interaction with Lck. Moreover, cells expressing this mutant form of LAT showed a statistically significant increase of proximal intracellular signals such as phosphorylation of LAT in tyrosine residues 171 and 191, and also enhanced ZAP70 phosphorylation approaching borderline statistical significance (p = 0.051). Nevertheless, downstream signals such as Ca2+ influx or MAPK pathways were partially inhibited. Overall, our data reveal that LAT-Lck interaction constitutes a key element regulating proximal intracellular signals coming from the TCR/CD3 complex.
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Affiliation(s)
- Mikel M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Isaac Narbona-Sánchez
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Cecilia M Fernandez-Ponce
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Inmaculada Vico-Barranco
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | | | - Michael L Dustin
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Kennedy Institute of Rheumatology, The University of Oxford, Headington, United Kingdom
| | - Arkadiusz Miazek
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Mª Carmen Duran-Ruiz
- Department of Biomedicine, Biotechnology and Public Health (Biochemistry), University of Cádiz, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Francisco García-Cózar
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Enrique Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
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Tyuryaeva II, Lyublinskaya OG, Podkorytov IS, Skrynnikov NR. Origin of anti-tumor activity of the cysteine-containing GO peptides and further optimization of their cytotoxic properties. Sci Rep 2017; 7:40217. [PMID: 28091523 PMCID: PMC5238392 DOI: 10.1038/srep40217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 12/05/2016] [Indexed: 12/28/2022] Open
Abstract
Antitumor GO peptides have been designed as dimerization inhibitors of prominent oncoprotein mucin 1. In this study we demonstrate that activity of GO peptides is independent of the level of cellular expression of mucin 1. Furthermore, these peptides prove to be broadly cytotoxic, causing cell death also in normal cells such as dermal fibroblasts and endometrial mesenchymal stem cells. To explore molecular mechanism of their cytotoxicity, we have designed and tested a number of new peptide sequences containing the key CxC or CxxC motifs. Of note, these sequences bear no similarity to mucin 1 except that they also contain a pair of proximal cysteines. Several of the new peptides turned out to be significantly more potent than their GO prototypes. The results suggest that cytotoxicity of these peptides stems from their (moderate) activity as disulfide oxidoreductases. It is expected that such peptides, which we have termed DO peptides, are involved in disulfide-dithiol exchange reaction, resulting in formation of adventitious disulfide bridges in cell proteins. In turn, this leads to a partial loss of protein function and rapid onset of apoptosis. We anticipate that coupling DO sequences with tumor-homing transduction domains can create a potentially valuable new class of tumoricidal peptides.
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Affiliation(s)
- Irina I. Tyuryaeva
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Olga G. Lyublinskaya
- Department of Intracellular Signaling and Transport, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Ivan S. Podkorytov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Nikolai R. Skrynnikov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg 199034, Russia
- Department of Chemistry, Purdue University, West Lafayette IN 47907, USA
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Bacchelli C, Moretti FA, Carmo M, Adams S, Stanescu HC, Pearce K, Madkaikar M, Gilmour KC, Nicholas AK, Woods CG, Kleta R, Beales PL, Qasim W, Gaspar HB. Mutations in linker for activation of T cells (LAT) lead to a novel form of severe combined immunodeficiency. J Allergy Clin Immunol 2016; 139:634-642.e5. [PMID: 27522155 DOI: 10.1016/j.jaci.2016.05.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/17/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Signaling through the T-cell receptor (TCR) is critical for T-cell development and function. Linker for activation of T cells (LAT) is a transmembrane adaptor signaling molecule that is part of the TCR complex and essential for T-cell development, as demonstrated by LAT-deficient mice, which show a complete lack of peripheral T cells. OBJECTIVE We describe a pedigree affected by a severe combined immunodeficiency phenotype with absent T cells and normal B-cell and natural killer cell numbers. A novel homozygous frameshift mutation in the gene encoding for LAT was identified in this kindred. METHODS Genetic, molecular, and functional analyses were used to identify and characterize the LAT defect. Clinical and immunologic analysis of patients was also performed and reported. RESULTS Homozygosity mapping was used to identify potential defective genes. Sanger sequencing of the LAT gene showed a mutation that resulted in a premature stop codon and protein truncation leading to complete loss of function and loss of expression of LAT in the affected family members. We also demonstrate loss of LAT expression and lack of TCR signaling restoration in LAT-deficient cell lines reconstituted with a synthetic LAT gene bearing this severe combined immunodeficiency mutation. CONCLUSION For the first time, the results of this study show that inherited LAT deficiency should be considered in patients with combined immunodeficiency with T-cell abnormalities.
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Affiliation(s)
- Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Federico A Moretti
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Marlene Carmo
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Stuart Adams
- Bone Marrow Transplantation, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Horia C Stanescu
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Kerra Pearce
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Manisha Madkaikar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Pediatric Immunology and Leukocyte Biology, National Institute of Immunohematology, ICMR, Mumbai, India
| | - Kimberly C Gilmour
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Adeline K Nicholas
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - C Geoffrey Woods
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Robert Kleta
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Phil L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Waseem Qasim
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - H Bobby Gaspar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom.
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Phorbol ester-mediated re-expression of endogenous LAT adapter in J.CaM2 cells: a model for dissecting drivers and blockers of LAT transcription. Genes Immun 2016; 17:313-20. [PMID: 27278128 PMCID: PMC4972999 DOI: 10.1038/gene.2016.25] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/05/2016] [Accepted: 05/06/2016] [Indexed: 12/31/2022]
Abstract
Linker for activation of T cells (LAT) is a raft-associated, transmembrane adapter protein critical for T-cell development and function. LAT expression is transiently upregulated upon T-cell receptor (TCR) engagement, but molecular mechanisms conveying TCR signaling to enhanced LAT transcription are not fully understood. Here we found that a Jurkat subline J.CaM2, initially characterized as LAT deficient, conditionally re-expressed LAT upon the treatment with a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). We took advantage of the above observation for studying cis-elements and trans-acting factors contributing to the activation-induced expression of LAT. We identified a LAT gene region spanning nucleotide position −14 to +357 relative to the ATG start codon as containing novel cis-regulatory elements that were able to promote PMA-induced reporter transcription in the absence of the core LAT promoter. Interestingly, a point mutation in LAT intron 1, identified in J.CaM2 cells, downmodulated LAT promoter activity by 50%. Mithramycin A, a selective Sp1 DNA-binding inhibitor, abolished LAT expression upon PMA treatment as did calcium ionophore ionomycin (Iono) and valproic acid (VPA), widely used as an anti-epileptic drug. Our data introduce J.CaM2 cells as a model for dissecting drivers and blockers of activation induced expression of LAT.
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Arbulo-Echevarria MM, Muñoz-Miranda JP, Caballero-García A, Poveda-Díaz JL, Fernández-Ponce C, Durán-Ruiz MC, Miazek A, García-Cózar F, Aguado E. Non-T cell activation linker (NTAL) proteolytic cleavage as a terminator of activatory intracellular signals. J Leukoc Biol 2016; 100:351-60. [PMID: 26830332 DOI: 10.1189/jlb.2a0715-318r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/21/2016] [Indexed: 12/13/2022] Open
Abstract
Non-T cell activation linker is an adaptor protein that is tyrosine phosphorylated upon cross-linking of immune receptors expressed on B lymphocytes, NK cells, macrophages, basophils, or mast cells, allowing the recruitment of cytosolic mediators for downstream signaling pathways. Fas receptor acts mainly as a death receptor, and when cross-linked with Fas ligand, many proteins are proteolytically cleaved, including several signaling molecules in T and B cells. Fas receptor triggering also interferes with TCR intracellular signals, probably by means of proteolytic cleavage of several adaptor proteins. We have previously found that the adaptor linker for activation of T cells, evolutionarily related to non-T cell activation linker, is cleaved upon proapoptotic stimuli in T lymphocytes and thymocytes, in a tyrosine phosphorylation-dependent fashion. Here, we describe non-T cell activation linker proteolytic cleavage triggered in human B cells and monocytes by Fas cross-linking and staurosporine treatment. Non-T cell activation linker is cleaved, producing an N-terminal fragment of ∼22 kDa, and such cleavage is abrogated in the presence of caspase 8/granzyme B and caspase 3 inhibitors. Moreover, we have identified an aspartic acid residue at which non-T cell activation linker is cleaved, which similar to linker for activation of T cells, this aspartic acid residue is located close to tyrosine and serine residues, suggesting an interdependence of phosphorylation and proteolytic cleavage. Consistently, induction of non-T cell activation linker phosphorylation by pervanadate inhibits its cleavage. Interestingly, the truncated isoform of non-T cell activation linker, generated after cleavage, has a decreased signaling ability when compared with the full-length molecule. Altogether, our results suggest that cleavage of transmembrane adaptors constitutes a general mechanism for signal termination of immune receptors.
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Affiliation(s)
- Mikel M Arbulo-Echevarria
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Juan Pedro Muñoz-Miranda
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Andrés Caballero-García
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - José L Poveda-Díaz
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Cecilia Fernández-Ponce
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - M Carmen Durán-Ruiz
- Department of Biomedicine, Biotechnology and Public Health (Biochemistry), University of Cádiz, Cádiz, Spain
| | - Arkadiusz Miazek
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
| | - Francisco García-Cózar
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Enrique Aguado
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain,
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7
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Kłossowicz M, Marek-Bukowiec K, Arbulo-Echevarria MM, Ścirka B, Majkowski M, Sikorski AF, Aguado E, Miazek A. Identification of functional, short-lived isoform of linker for activation of T cells (LAT). Genes Immun 2014; 15:449-56. [PMID: 25008862 DOI: 10.1038/gene.2014.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 05/04/2014] [Accepted: 05/23/2014] [Indexed: 12/13/2022]
Abstract
Linker for activation of T cells (LAT) is a transmembrane adaptor protein playing a key role in the development, activation and maintenance of peripheral homeostasis of T cells. In this study we identified a functional isoform of LAT. It originates from an intron 6 retention event generating an in-frame splice variant of LAT mRNA denoted as LATi6. Comparison of LATi6 expression in peripheral blood leukocytes of human and several other mammalian species revealed that it varied from being virtually absent in the mouse to being predominant in the cow. Analysis of LAT isoform frequency expressed from minigene splicing reporters carrying loss- or gain-of-function point mutations within intronic polyguanine sequences showed that these elements are critical for controlling the intron 6 removal. The protein product of LATi6 isoform (LATi6) ectopically expressed in LAT-deficient JCam 2.5 cell line localized correctly to subcellular compartments and supported T-cell receptor signaling but differed from the canonical LAT protein by displaying a shorter half-life and mediating an increased interleukin-2 secretion upon prolonged CD3/CD28 crosslinking. Altogether, our data suggest that the appearance of LATi6 isoform is an evolutionary innovation that may contribute to a more efficient proofreading control of effector T-cell response.
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Affiliation(s)
- M Kłossowicz
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - K Marek-Bukowiec
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - B Ścirka
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M Majkowski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - A F Sikorski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - E Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - A Miazek
- 1] Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland [2] Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
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