The accumulation of leukocytes in non-lymphoid tissues and their structural organization into tertiary lymphoid structures (TLS), a process known as ectopic lymphoid neogenesis (ELN), is observed in response to chronic inflammation and in the target organ of several autoimmune diseases. TLS strongly resemble secondary lymphoid organs with specialised high-endothelial venules (HEV), segregated B/T cell areas and presence of follicular dendritic cells (FDC) networks promoting in situ affinity maturation of the antibody response. TLS have been associated with a growing number of autoimmune conditions and usually their presence is prognostic for undesirable disease progression. In Sjögren’s syndrome (SS), an autoimmune disease affecting the salivary and lachrymal glands leading to exocrine dysfunction, TLS develop in the salivary glands (SG) of around one-third of the patients. The immunobiology of the SG and the pathogenesis of SS have been poorly clarified and to date a robust and reproducible inducible animal model of SS and TLS in the SG is still absent. In my PhD, I developed and validated a novel inducible model of ELN in murine SG that also reproduces several features of SS. The retrograde administration of a replication-deficient adenovirus (AdV) in the SGs of wild-type C57Bl/6 mice was able to induce within three weeks fully formed TLS that displayed B/T cell segregation, FDC networks, HEVs and were positive for markers of germinal centres. Moreover, the AdV-treated mice showed a significant reduction of salivary flow and in 75% of the cases development of anti-nuclear antibodies.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23100号 / 医博第4727号 / 新制||医||1050(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 平井 豊博, 教授 河本 宏, 教授 竹内 理 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introduction: les follicules lymphoïdes (FL) sont absents du poumon normal mais ont été décrits dans les poumons de patients atteints de mucoviscidose ou de dilatations de bronches non mucoviscidosiques, suggérant un rôle pour l’infection bronchique dans la néogenèse lymphoïde (NL). Nous avons étudié la dynamique de la néogenèse lymphoïde dans l’infection bactérienne. Méthodes: les souris C57BL/6 ont reçu une instillation intratrachéale de billes d’agarose contenant du PAO1 ou du S. aureus (106 CFU/animal) permettant une infection prolongée et ont été comparées à des souris contrôles (billes stériles ou absence de billes). Les souris ont été sacrifiées à J1, J4, J7 et J14. Résultats: l’instillation unique de billes d’agarose contenant du PAO1 ou du S. aureus induit en 14 jours des FL fonctionnels situés sous l’épithélium en regard des zones d’infection. Le marquage pour CXCL12 et CXCL13 est faible chez contrôles, mais présent dans l’épithélium (CXCL13) dès J1 et présent également dans les FL (CXCL12 et CXCL13) à J14 chez les souris infectées. Le traitement des souris par un anticorps anti CXCL12 ou anti CXCL13 n’inhibe pas la formation des FL induite par l’infection à PAO1. Conclusion: nos données suggèrent un rôle pour l’infection bactérienne prolongée et l’épithélium respiratoire dans la NL des bronchopathies chroniques. Notre modèle permet d’évaluer les mécanismes de la formation et de persistance des FL dans le poumon. / Introduction: lymphoid follicles (LF) are absent in normal lungs, but are described in lungs of subjects with cystic fibrosis (CF) or non-CF bronchiectasis, suggesting a role for bacterial infection in lymphoid neogenesis. We aimed to study the dynamic of pulmonary lymphoid neogenesis (LN) during bacterial infection. Methods: C57BL/6 mice were instilled intratracheally with PAO1- or S. aureus-coated (1.106 CFU/mouse) agarose beads (which produced prolonged airway infection) and compared to controls (sterile beads or no instillation). Mice were sacrificed on day (d)1, d4, d7, and d14 after instillation. Results: chronic pulmonary infection with PAO1 or S. aureus induced organised LF in 14 days after a single challenge with PAO1- or S. aureus-coated beads. Bacteria- induced LF were exclusively localized in the subepithelium of infected airways. Staining for CXCL12 and CXCL13 was weak in airway epithelium of controls, but was positive in airway epithelium (CXCL13) at 1 day and in LF (both) of infected mice at 14 days. Treatment with anti CXCL12 or anti CXCL13 Ab did not reduce LN induced by PAO1 infection. Conclusions: chronic bacterial infection and respiratory epithelium could contribute to LN in chronic airway diseases. Our unique model allows to study mechanisms for the formation and maintenance of lung LF.