Clonal expansions of CD8+ T cells in latently HSV-1-infected human trigeminal ganglia

Herpes simplex virus type 1 latency in trigeminal ganglia (TG) is accompanied by a chronic immune cell infiltration. The aim of this study was to analyse the T-cell receptor β-chain repertoire in latently HSV-1 infected human TG. Using complementarity-determining region 3 spectratyping, 74 expanded β-chain sequences were identified in five TG. No clone appeared in more than one subject. Similar clones were present in the right and the left TG of two subjects. This indicates that these T cells are primed in the periphery and recognise the same antigen in the TG of both side

Die Rolle von CD4 Helfer T Zellen und sialylierten antigen-spezifischen IgG Antikörpern in rheumatischen Autoimmunerkrankungen

Systemischer Lupus Erythematodes (SLE) und Rheumatoide Arthritis (RA) sind rheumatische Autoimmunerkrankungen, die durch die Entstehung von pathogenen IgG Autoantikörper charakterisiert sind. SLE ist eine systemische Autoimmunerkrankung, die sich durch die Entstehung von IgG Autoantikörpern spezifisch für anti-nukleare Antigene auszeichnet. Diese lagern sich in Form von Immunkomplexen in verschiedenen Organen ab, was zu Organversagen führt. Pathogene IgG Autoantikörper gegen den Fc-Teil von IgGs (Rheumafaktor IgGs) und Kollagen Typ II findet man bei Patienten der RA, wobei hier spezifische Entzündungen der Gelenke charakteristisch sind. In Autoimmunerkrankungen wie SLE und RA stimulieren T Zellen autoreaktive B Zellen zur Differenzierung in Keimzentren, welche daraufhin hoch-affine IgG Antikörper sekretieren. Darüber hinaus können T Zellen zur Autoimmunität beitragen indem sie Zytokine produzieren, welche die Aktivierung von Immunzellen des angeborenen Immunsystems wie Makrophagen und Neutrophile und deren Rekrutierung in die Zielorgane fordern. Das Ziel dieser Arbeit war es, die Rolle von T Zellen, die an der Pathogenese von SLE und RA beteiligt sind, zu untersuchen. Hierfür wurden Lupus-anfällige RIIB-/-TLR9-/- Mause bzw. das Kollagen-induzierte Arthritis (CIA) Mausmodell verwendet. Die Analyse der RIIB-/-TLR9-/- Mause zeigte eine Akkumulation von Th1 und Th17 Zellen im Vergleich zu Wildtyp-Mausen. Die zusätzliche Deletion der Rezeptoren IFNR1 oder IL-17RA in RIIB-/-TLR9-/- Mausen zeigte deutlich, dass sowohl Th1 als auch Th17 Zellen an der Pathogenese der Lupusnephritis beteiligt sind. Th1 Zellen verhindern die Entstehung von Nephritis durch eine vollständige Hemmung der IgG2c Autoantikörperentstehung und eine signifikante Reduktion von IgG2b. Th17 Zellen beeinflussen die Differenzierung von B Zellen in Keimzentren in sekundären lymphoiden Organen und die Infiltration von Makrophagen ins Nierengewebe. In dem CIA Mausmodel fur RA reduzierte ich die Th17 Differenzierung mit Hilfe eines IL-23R blockierenden Antikörpers. Dies führte zu verminderten Arthritissymptomen und reduzierter Anzahl an erkrankten Mäusen. Die Daten aus beiden Krankheitsmodellen zeigen, dass ein Präparat, welches die Entstehung von Th17 und/oder Th1 Zellen verhindert, ein vielversprechendes Medikament zur Behandlung von Autoimmunerkrankungen darstellen konnte. Daraufhin habe ich antigen-spezifische sialylierte IgGs als therapeutischen Ansatz zur Modifikation der Th1 und Th17 Differenzierung untersucht. Es ist bekannt, dass deglykosylierte Autoantikörper von RA-Patienten pro-inflammatorische Effekte vermitteln. Außerdem vermitteln hochsialylierte IgGs im IVIG entzündungshemmende Reaktionen auf antigen-unspezifische Weise. In dieser Arbeit wurde die Wirkung von sialylierten und nicht-sialylierten kollagen II spezifischen IgGs mit IVIG hinsichtlich der zellularen und humoralen Immunantwort im CIA Mausmodell verglichen. Meine Daten zeigen, dass eine niedrige Dosis von sialylierten Kollagen II-spezifischen IgG-Antikorpern ausreicht, um die Entstehung von Th17 Zellen und pathogenen IgG Autoantikorpern zu vermindern und damit die Entstehung von CIA zu verhindern. Die hier gewonnenen Daten belegen, dass die Glykosylierung von antigen-spezifischen Antikörpern entscheidend ist, um anti-inflammatorische Effekte auslösen zu können und damit Schutz vor entzündlichen Immunreaktionen zu bieten. Außerdem zeigt diese Arbeit, dass sialylierte antigen-spezifische IgG-Antikörper in Zukunft die immunsuppressive Wirkung von IVIG ersetzen konnten.Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are rheumatic autoimmune diseases characterized by IgG autoantibody production. The systemic inflammation observed in SLE patients causes damage to multiple organs due to autoantibodies specific for various nuclear antigens. Otherwise, autoantibodies found in RA patients are mainly directed against the Fc-part of IgG (rheumatoid factor) and collagen type II causing inflammation primarily involving the joints and therefore resulting in destruction of cartilage. T cells contribute to autoimmunity by stimulating the activation and functional differentiation of autoreactive B cells in germinal centers (GCs), which secrete high-affinity, isotypeswitched autoantibodies. Furthermore, T cells facilitate and enhance autoimmunity by secretion of cytokines that promote recruitment and activation of innate immune cells such as macrophages and neutrophils into target organs. The aim of this study was to investigate different T cell subsets involved in the pathogenesis of SLE and RA using lupus prone RIIB-/-TLR9-/- mice and the collagen-induced arthritis (CIA) mouse model, respectively. Analysis of RIIB-/-TLR9-/- mice showed an increase of Th1 and Th17 cell differentiation compared to wild-type mice. Deleting IFNR1 or IL-17RA in RIIB-/-TLR9-/- mice made clear that both CD4+ T helper cell subsets contribute to the pathogenesis of lupus nephritis. Th1 cells probably prevent disease onset by complete inhibition of IgG2c autoantibody development. Th17 cells influence germinal center formation in secondary lymphoid organs and macrophage infiltration into renal tissues. Thus, a reagent targeting both Th1 and Th17 cells might be a promising tool to treat SLE. Investigation of the role of Th17 cells in the CIA mouse model showed reduced disease severity and disease incidence. This was due to impaired macrophage and neutrophil differentiation upon inhibition of Th17 cell differentiation by administration of an anti-IL-23R antibody. Here, I used sialylated CII-specific IgG antibodies to investigate its effect on Th17 differentiation in the CIA mouse model. Recent studies showed that de-glycosylated autoantibodies mediate pro-inflammatory responses during the pathogenesis of RA. Furthermore, sialylated IgGs found in IVIG mediate anti-inflammatory responses antigen-unspecifically. In this work, I compared the effect of sialylated and non-sialylated antigen-specific IgGs to IVIG regarding the cellular and humoral immune response in the CIA mouse model. My data show for the first time that low dose of antigen-specific sialylated IgG antibodies are sufficient to inhibit the development of CIA by inhibiting Th17 cell differentiation and pathogenic IgG autoantibody development. The data provide evidence that enzymatic glycosylation of antigen-specific antibodies is crucial to switch their effector function triggering anti-inflammatory effects and thus protecting from inflammatory immune responses. Furthermore, I provide evidence that sialylated antigen-specific IgG antibodies could substitute the immunosuppressive effect of IVIG in the future

Sialylated Autoantigen-Reactive IgG Antibodies Attenuate Disease Development in Autoimmune Mouse Models of Lupus Nephritis and Rheumatoid Arthritis

Pro- and anti-inflammatory effector functions of IgG antibodies (Abs) depend on their subclass and Fc glycosylation pattern. Accumulation of non-galactosylated (agalactosylated; G0) IgG Abs in the serum of rheumatoid arthritis and systemic lupus erythematosus (SLE) patients reflects severity of the diseases. In contrast, sialylated IgG Abs are responsible for anti-inflammatory effects of the intravenous immunoglobulin (pooled human serum IgG from healthy donors), administered in high doses (2 g/kg) to treat autoimmune patients. However, whether low amounts of sialylated autoantigen-reactive IgG Abs can also inhibit autoimmune diseases is hardly investigated. Here, we explore whether sialylated autoantigen-reactive IgG Abs can inhibit autoimmune pathology in different mouse models. We found that sialylated IgG auto-Abs fail to induce inflammation and lupus nephritis in a B cell receptor (BCR) transgenic lupus model, but instead are associated with lower frequencies of pathogenic Th1, Th17 and B cell responses. In accordance, the transfer of small amounts of immune complexes containing sialylated IgG Abs was sufficient to attenuate the development of nephritis. We further showed that administration of sialylated collagen type II (Col II)-specific IgG Abs attenuated the disease symptoms in a model of Col II-induced arthritis and reduced pathogenic Th17 cell and autoantigen-specific IgG Ab responses. We conclude that sialylated autoantigen-specific IgG Abs may represent a promising tool for treating pathogenic T and B cell immune responses in autoimmune diseases

Clonal expansions of CD8(+) T cells in latently HSV-1-infected human trigeminal ganglia

Herpes simplex virus type 1 latency in trigeminal ganglia (TG) is accompanied by a chronic immune cell infiltration. The aim of this study was to analyse the T-cell receptor beta-chain repertoire in latently HSV-1 infected human TG. Using complementarity-determining region 3 spectratyping, 74 expanded beta-chain sequences were identified in five TG. No clone appeared in more than one subject. Similar clones were present in the right and the left TG of two subjects. This indicates that these T cells are primed in the periphery and recognise the same antigen in the TG of both sides

Tolerance induction with T cell-dependent protein antigens induces regulatory sialylated IgGs

Background: Under inflammatory conditions, T cell-dependent (TD) protein antigens induce proinflammatory T-and B-cell responses. In contrast, tolerance induction by TD antigens without costimulation triggers the development of regulatory T cells. Under both conditions, IgG antibodies are generated, but whether they have different immunoregulatory functions remains elusive. Objective: It was shown recently that proinflammatory or anti-inflammatory effector functions of IgG molecules are determined by different Fc N-linked glycosylation patterns. We sought to examine the Fc glycosylation and anti-inflammatory quality of IgG molecules formed on TD tolerance induction. Methods: We administered chicken ovalbumin (OVA) with or without costimulus to mice and analyzed OVA-reactive IgG Fc glycosylation. The anti-inflammatory function of differentially glycosylated anti-OVA IgGs was further investigated in studies with dendritic cell cultures and in an in vivo model of allergic airway disease. Additionally, we analyzed the Fc glycosylation pattern of birch pollen-reactive serum IgGs after successful allergen-specific immunotherapy in patients. Results: Stimulation with TD antigens under inflammatory conditions induces plasma cells expressing low levels of alpha 2,6-sialyltransferase and producing desialylated IgGs. In contrast, plasma cells induced on tolerance induction did not downregulate alpha 2,6-sialyltransferase expression and secreted immunosuppressive sialylated IgGs that were sufficient to block antigen-specific T- and B-cell responses, dendritic cell maturation, and allergic airway inflammation. Importantly, successful specific immunotherapy in allergic patients also induced sialylated allergen-specific IgGs. Conclusions: Our data show a novel antigen-specific immunoregulatory mechanism mediated by anti-inflammatory sialylated IgGs that are formed on TD tolerance induction. These findings might help to develop novel antigen-specific therapies for the treatment of allergy and autoimmunity. (J Allergy Clin Immunol 2012;129:1647-55.

Presentation_1_Sialylated Autoantigen-Reactive IgG Antibodies Attenuate Disease Development in Autoimmune Mouse Models of Lupus Nephritis and Rheumatoid Arthritis.PDF

<p>Pro- and anti-inflammatory effector functions of IgG antibodies (Abs) depend on their subclass and Fc glycosylation pattern. Accumulation of non-galactosylated (agalactosylated; G0) IgG Abs in the serum of rheumatoid arthritis and systemic lupus erythematosus (SLE) patients reflects severity of the diseases. In contrast, sialylated IgG Abs are responsible for anti-inflammatory effects of the intravenous immunoglobulin (pooled human serum IgG from healthy donors), administered in high doses (2 g/kg) to treat autoimmune patients. However, whether low amounts of sialylated autoantigen-reactive IgG Abs can also inhibit autoimmune diseases is hardly investigated. Here, we explore whether sialylated autoantigen-reactive IgG Abs can inhibit autoimmune pathology in different mouse models. We found that sialylated IgG auto-Abs fail to induce inflammation and lupus nephritis in a B cell receptor (BCR) transgenic lupus model, but instead are associated with lower frequencies of pathogenic Th1, Th17 and B cell responses. In accordance, the transfer of small amounts of immune complexes containing sialylated IgG Abs was sufficient to attenuate the development of nephritis. We further showed that administration of sialylated collagen type II (Col II)-specific IgG Abs attenuated the disease symptoms in a model of Col II-induced arthritis and reduced pathogenic Th17 cell and autoantigen-specific IgG Ab responses. We conclude that sialylated autoantigen-specific IgG Abs may represent a promising tool for treating pathogenic T and B cell immune responses in autoimmune diseases.</p