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  1. Article: The Relative Positioning of B and T Cell Epitopes Drives Immunodominance.

    Biavasco, Riccardo / De Giovanni, Marco

    Vaccines

    2022  Volume 10, Issue 8

    Abstract: Humoral immunity is crucial for protection against invading pathogens. Broadly neutralizing antibodies (bnAbs) provide sterilizing immunity by targeting conserved regions of viral variants and represent the goal of most vaccination approaches. While ... ...

    Abstract Humoral immunity is crucial for protection against invading pathogens. Broadly neutralizing antibodies (bnAbs) provide sterilizing immunity by targeting conserved regions of viral variants and represent the goal of most vaccination approaches. While antibodies can be selected to bind virtually any region of a given antigen, the consistent induction of bnAbs in the context of influenza and HIV has represented a major roadblock. Many possible explanations have been considered; however, none of the arguments proposed to date seem to fully recapitulate the observed counter-selection for broadly protective antibodies. Antibodies can influence antigen presentation by enhancing the processing of CD4 epitopes adjacent to the binding region while suppressing the overlapping ones. We analyze the relative positioning of dominant B and T cell epitopes in published antigens that elicit strong and poor humoral responses. In strong immunogenic antigens, regions bound by immunodominant antibodies are frequently adjacent to CD4 epitopes, potentially boosting their presentation. Conversely, poorly immunogenic regions targeted by bnAbs in HIV and influenza overlap with clusters of dominant CD4 epitopes, potentially conferring an intrinsic disadvantage for bnAb-bearing B cells in germinal centers. Here, we propose the theory of immunodominance relativity, according to which the relative positioning of immunodominant B and CD4 epitopes within a given antigen drives immunodominance. Thus, we suggest that the relative positioning of B-T epitopes may be one additional mechanism that cooperates with other previously described processes to influence immunodominance. If demonstrated, this theory can improve the current understanding of immunodominance, provide a novel explanation for HIV and influenza escape from humoral responses, and pave the way for a new rational design of universal vaccines.
    Language English
    Publishing date 2022-07-31
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2703319-3
    ISSN 2076-393X
    ISSN 2076-393X
    DOI 10.3390/vaccines10081227
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: GPR35 and mediators from platelets and mast cells in neutrophil migration and inflammation.

    De Giovanni, Marco / Chen, Hongwen / Li, Xiaochun / Cyster, Jason G

    Immunological reviews

    2023  Volume 317, Issue 1, Page(s) 187–202

    Abstract: Neutrophil recruitment from circulation to sites of inflammation is guided by multiple chemoattractant cues emanating from tissue cells, immune cells, and platelets. Here, we focus on the function of one G-protein coupled receptor, GPR35, in neutrophil ... ...

    Abstract Neutrophil recruitment from circulation to sites of inflammation is guided by multiple chemoattractant cues emanating from tissue cells, immune cells, and platelets. Here, we focus on the function of one G-protein coupled receptor, GPR35, in neutrophil recruitment. GPR35 has been challenging to study due the description of multiple ligands and G-protein couplings. Recently, we found that GPR35-expressing hematopoietic cells respond to the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). We discuss distinct response profiles of GPR35 to 5-HIAA compared to other ligands. To place the functions of 5-HIAA in context, we summarize the actions of serotonin in vascular biology and leukocyte recruitment. Important sources of serotonin and 5-HIAA are platelets and mast cells. We discuss the dynamics of cell migration into inflamed tissues and how multiple platelet and mast cell-derived mediators, including 5-HIAA, cooperate to promote neutrophil recruitment. Additional actions of GPR35 in tissue physiology are reviewed. Finally, we discuss how clinically approved drugs that modulate serotonin uptake and metabolism may influence 5-HIAA-GPR35 function, and we speculate about broader influences of the GPR35 ligand-receptor system in immunity and disease.
    MeSH term(s) Humans ; Mast Cells ; Neutrophils ; Blood Platelets ; Ligands ; Serotonin/metabolism ; Hydroxyindoleacetic Acid/metabolism ; Inflammation ; Cell Movement ; Neutrophil Infiltration ; Receptors, G-Protein-Coupled/metabolism
    Chemical Substances Ligands ; Serotonin (333DO1RDJY) ; Hydroxyindoleacetic Acid (54-16-0) ; GPR35 protein, human ; Receptors, G-Protein-Coupled
    Language English
    Publishing date 2023-03-16
    Publishing country England
    Document type Journal Article ; Review ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 391796-4
    ISSN 1600-065X ; 0105-2896
    ISSN (online) 1600-065X
    ISSN 0105-2896
    DOI 10.1111/imr.13194
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Relative positioning of B and T cell epitopes drives immunodominance.

    Biavasco, Riccardo / De Giovanni, Marco

    bioRxiv

    Abstract: Humoral immunity is crucial for protection against invading pathogens. Broadly neutralizing antibodies (bnAbs) provide sterilizing immunity by targeting conserved regions of viral variants and represent the goal of most vaccination approaches. While ... ...

    Abstract Humoral immunity is crucial for protection against invading pathogens. Broadly neutralizing antibodies (bnAbs) provide sterilizing immunity by targeting conserved regions of viral variants and represent the goal of most vaccination approaches. While antibodies can be selected to bind virtually any region of a given antigen, consistent induction of bnAbs in the context of influenza and HIV has been representing a major roadblock. Many possible explanations have been considered, however, none of the arguments proposed so far seems to fully recapitulate the observed counter-selection for broadly protective antibodies. Antibodies can influence antigen presentation by enhancing the processing of CD4 epitopes adjacent to the binding region while suppressing the overlapping ones. We analyzed the relative positioning of dominant B and T cell epitopes in published antigens that elicit strong and poor humoral responses. In strong immunogenic antigens, regions bound by immunodominant antibodies are frequently adjacent to CD4 epitopes, potentially boosting their presentation. Conversely, poorly immunogenic regions targeted by bnAbs in HIV and influenza overlap with clusters of dominant CD4 epitopes, potentially conferring an intrinsic disadvantage for bnAb-bearing B cells in germinal centers. Here we propose the theory of immunodominance relativity, according to which relative positioning of immunodominant B and CD4 epitopes within a given antigen drives immunodominance. Thus, we suggest that relative positioning of B-T epitopes may be one additional mechanism that cooperates with other previously described processes to influence immunodominance. If demonstrated, this theory can improve the current understanding of immunodominance, provide a novel explanation on HIV and influenza escape from humoral responses, and pave the way for new rational design of universal vaccines.
    Keywords covid19
    Language English
    Publishing date 2022-02-18
    Publisher Cold Spring Harbor Laboratory
    Document type Article ; Online
    DOI 10.1101/2022.02.17.480954
    Database COVID19

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  4. Article ; Online: GPR35 promotes neutrophil recruitment in response to serotonin metabolite 5-HIAA.

    De Giovanni, Marco / Tam, Hanson / Valet, Colin / Xu, Ying / Looney, Mark R / Cyster, Jason G

    Cell

    2022  Volume 185, Issue 6, Page(s) 1103–1104

    Language English
    Publishing date 2022-03-17
    Publishing country United States
    Document type Published Erratum
    ZDB-ID 187009-9
    ISSN 1097-4172 ; 0092-8674
    ISSN (online) 1097-4172
    ISSN 0092-8674
    DOI 10.1016/j.cell.2022.03.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: GPR35 promotes neutrophil recruitment in response to serotonin metabolite 5-HIAA.

    De Giovanni, Marco / Tam, Hanson / Valet, Colin / Xu, Ying / Looney, Mark R / Cyster, Jason G

    Cell

    2022  Volume 185, Issue 5, Page(s) 815–830.e19

    Abstract: Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils ... ...

    Abstract Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils are less recruited from blood vessels into inflamed tissue, and the mice are less efficient in clearing peritoneal bacteria. Using a bioassay, we find that serum and activated platelet supernatant stimulate GPR35, and we identify the platelet-derived serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) as a GPR35 ligand. GPR35 function in neutrophil recruitment is strongly dependent on platelets, with the receptor promoting transmigration across platelet-coated endothelium. Mast cells also attract GPR35
    MeSH term(s) Animals ; Hydroxyindoleacetic Acid/metabolism ; Inflammation/metabolism ; Ligands ; Mice ; Neutrophil Infiltration ; Neutrophils/metabolism ; Receptors, G-Protein-Coupled/metabolism ; Serotonin/metabolism
    Chemical Substances GPR35 protein, mouse ; Ligands ; Receptors, G-Protein-Coupled ; Serotonin (333DO1RDJY) ; Hydroxyindoleacetic Acid (54-16-0)
    Language English
    Publishing date 2022-02-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 187009-9
    ISSN 1097-4172 ; 0092-8674
    ISSN (online) 1097-4172
    ISSN 0092-8674
    DOI 10.1016/j.cell.2022.01.010
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Platelets and mast cells promote pathogenic eosinophil recruitment during invasive fungal infection via the 5-HIAA-GPR35 ligand-receptor system.

    De Giovanni, Marco / Dang, Eric V / Chen, Kevin Y / An, Jinping / Madhani, Hiten D / Cyster, Jason G

    Immunity

    2023  Volume 56, Issue 7, Page(s) 1548–1560.e5

    Abstract: Cryptococcus neoformans is the leading cause of fungal meningitis and is characterized by pathogenic eosinophil accumulation in the context of type-2 inflammation. The chemoattractant receptor GPR35 is expressed by granulocytes and promotes their ... ...

    Abstract Cryptococcus neoformans is the leading cause of fungal meningitis and is characterized by pathogenic eosinophil accumulation in the context of type-2 inflammation. The chemoattractant receptor GPR35 is expressed by granulocytes and promotes their migration to the inflammatory mediator 5-hydroxyindoleacetic acid (5-HIAA), a serotonin metabolite. Given the inflammatory nature of cryptococcal infection, we examined the role of GPR35 in the circuitry underlying cell recruitment to the lung. GPR35 deficiency dampened eosinophil recruitment and fungal growth, whereas overexpression promoted eosinophil homing to airways and fungal replication. Activated platelets and mast cells were the sources of GPR35 ligand activity and pharmacological inhibition of serotonin conversion to 5-HIAA, or genetic deficiency in 5-HIAA production by platelets and mast cells resulted in more efficient clearance of Cryptococcus. Thus, the 5-HIAA-GPR35 axis is an eosinophil chemoattractant receptor system that modulates the clearance of a lethal fungal pathogen, with implications for the use of serotonin metabolism inhibitors in the treatment of fungal infections.
    MeSH term(s) Humans ; Eosinophils ; Hydroxyindoleacetic Acid ; Mast Cells ; Blood Platelets ; Ligands ; Receptors, Formyl Peptide ; Serotonin ; Cryptococcosis/microbiology ; Cryptococcosis/pathology ; Invasive Fungal Infections ; Receptors, G-Protein-Coupled/genetics
    Chemical Substances Hydroxyindoleacetic Acid (54-16-0) ; Ligands ; Receptors, Formyl Peptide ; Serotonin (333DO1RDJY) ; GPR35 protein, human ; Receptors, G-Protein-Coupled
    Language English
    Publishing date 2023-06-05
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1217235-2
    ISSN 1097-4180 ; 1074-7613
    ISSN (online) 1097-4180
    ISSN 1074-7613
    DOI 10.1016/j.immuni.2023.05.006
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: In vivo imaging of adaptive immune responses to viruses.

    De Giovanni, Marco / Iannacone, Matteo

    Current opinion in virology

    2017  Volume 28, Page(s) 102–107

    Abstract: Viral infections represent a major threat for mankind. The adaptive immune system plays a key role in both viral clearance and disease pathogenesis, and, accordingly, understanding how lymphocytes interact with different viruses is critical to design ... ...

    Abstract Viral infections represent a major threat for mankind. The adaptive immune system plays a key role in both viral clearance and disease pathogenesis, and, accordingly, understanding how lymphocytes interact with different viruses is critical to design more effective vaccination and therapeutic strategies. The recent advent of intravital microscopy has enabled the real-time visualization of the complex interplay between viruses and the ensuing adaptive immune response in living organisms. Here, we will review the most significant recent insights on antiviral adaptive immune responses obtained through intravital imaging. We will also discuss what challenges lie ahead and what we think are the most promising areas for future research.
    MeSH term(s) Adaptive Immunity ; Animals ; B-Lymphocytes/immunology ; B-Lymphocytes/virology ; Humans ; Immunity, Innate ; Intravital Microscopy ; Mice ; T-Lymphocytes/immunology ; T-Lymphocytes/virology ; Vaccination ; Virus Diseases/diagnostic imaging ; Virus Diseases/immunology ; Viruses
    Language English
    Publishing date 2017-12-26
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2611378-8
    ISSN 1879-6265 ; 1879-6257
    ISSN (online) 1879-6265
    ISSN 1879-6257
    DOI 10.1016/j.coviro.2017.12.002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: The role of type I interferons in CD4

    Kuka, Mirela / De Giovanni, Marco / Iannacone, Matteo

    Immunology letters

    2019  Volume 215, Page(s) 19–23

    Abstract: Type I interferons (IFNs) released upon viral infections play different and opposing roles in disease outcome. This pleiotropic effect is mainly influenced by the cellular sources, timing and target cells for these molecules. The effect of type I IFN ... ...

    Abstract Type I interferons (IFNs) released upon viral infections play different and opposing roles in disease outcome. This pleiotropic effect is mainly influenced by the cellular sources, timing and target cells for these molecules. The effect of type I IFN signaling on the activation and differentiation of antiviral CD4
    MeSH term(s) Animals ; CD4-Positive T-Lymphocytes/immunology ; CD4-Positive T-Lymphocytes/pathology ; Cell Differentiation/immunology ; Humans ; Interferon Type I/immunology ; Lymphocyte Activation ; Signal Transduction/immunology ; Virus Diseases/immunology ; Virus Diseases/pathology
    Chemical Substances Interferon Type I
    Language English
    Publishing date 2019-02-13
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 445150-8
    ISSN 1879-0542 ; 0165-2478
    ISSN (online) 1879-0542
    ISSN 0165-2478
    DOI 10.1016/j.imlet.2019.01.013
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Mast cells help organize the Peyer's patch niche for induction of IgA responses.

    De Giovanni, Marco / Vykunta, Vivasvan S / Biram, Adi / Chen, Kevin Y / Taglinao, Hanna / An, Jinping / Sheppard, Dean / Paidassi, Helena / Cyster, Jason G

    Science immunology

    2024  Volume 9, Issue 93, Page(s) eadj7363

    Abstract: Peyer's patches (PPs) are lymphoid structures situated adjacent to the intestinal epithelium that support B cell responses that give rise to many intestinal IgA-secreting cells. Induction of isotype switching to IgA in PPs requires interactions between B ...

    Abstract Peyer's patches (PPs) are lymphoid structures situated adjacent to the intestinal epithelium that support B cell responses that give rise to many intestinal IgA-secreting cells. Induction of isotype switching to IgA in PPs requires interactions between B cells and TGFβ-activating conventional dendritic cells type 2 (cDC2s) in the subepithelial dome (SED). However, the mechanisms promoting cDC2 positioning in the SED are unclear. Here, we found that PP cDC2s express GPR35, a receptor that promotes cell migration in response to various metabolites, including 5-hydroxyindoleacetic acid (5-HIAA). In mice lacking GPR35, fewer cDC2s were found in the SED, and frequencies of IgA
    MeSH term(s) Animals ; Mice ; Mast Cells ; Hydroxyindoleacetic Acid ; B-Lymphocytes ; Cell Movement ; Immunoglobulin A, Secretory ; Peyer's Patches ; Receptors, G-Protein-Coupled/genetics
    Chemical Substances Hydroxyindoleacetic Acid (54-16-0) ; Immunoglobulin A, Secretory ; GPR35 protein, mouse ; Receptors, G-Protein-Coupled
    Language English
    Publishing date 2024-03-01
    Publishing country United States
    Document type Journal Article
    ISSN 2470-9468
    ISSN (online) 2470-9468
    DOI 10.1126/sciimmunol.adj7363
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: GPR35 promotes neutrophil recruitment in response to serotonin metabolite 5-HIAA

    De Giovanni, Marco / Tam, Hanson / Valet, Colin / Xu, Ying / Looney, Mark R. / Cyster, Jason G.

    Cell. 2022 Mar. 03, v. 185, no. 5

    2022  

    Abstract: Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils ... ...

    Abstract Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils are less recruited from blood vessels into inflamed tissue, and the mice are less efficient in clearing peritoneal bacteria. Using a bioassay, we find that serum and activated platelet supernatant stimulate GPR35, and we identify the platelet-derived serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) as a GPR35 ligand. GPR35 function in neutrophil recruitment is strongly dependent on platelets, with the receptor promoting transmigration across platelet-coated endothelium. Mast cells also attract GPR35⁺ cells via 5-HIAA. Mice deficient in 5-HIAA show a loss of GPR35-mediated neutrophil recruitment to inflamed tissue. These findings identify 5-HIAA as a GPR35 ligand and neutrophil chemoattractant and establish a role for platelet- and mast cell-produced 5-HIAA in cell recruitment to the sites of inflammation and bacterial clearance.
    Keywords 5-hydroxyindoleacetic acid ; G-protein coupled receptors ; bioassays ; blood serum ; chemoattractants ; endothelium ; inflammation ; ligands ; metabolites ; neutrophils ; serotonin
    Language English
    Dates of publication 2022-0303
    Size p. 815-830.e19.
    Publishing place Elsevier Inc.
    Document type Article
    ZDB-ID 187009-9
    ISSN 1097-4172 ; 0092-8674
    ISSN (online) 1097-4172
    ISSN 0092-8674
    DOI 10.1016/j.cell.2022.01.010
    Database NAL-Catalogue (AGRICOLA)

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