Marzouki Soumaya, Zaraa Ines, Abdeladhim Maha, Benabdesselem Chaouki, Oliveira Fabiano, Kamhawi Shaden, Mokni Mourad, Louzir Hechmi, Valenzuela Jesus G, Ben Ahmed Melika
Laboratory of Transmission, Control and Immunobiology of Infections, LR11IPT02, Pasteur Institut de Tunis, Tunis, Tunisia.
Department of Dermatology, La Rabta Hospital Tunis, Tunis, Tunisia.
JCI Insight. 2020 Dec 3;5(23):123861. doi: 10.1172/jci.insight.123861.
A possible etiological link between the onset of endemic pemphigus in Tunisia and bites of Phlebotomus papatasi, the vector of zoonotic cutaneous leishmaniasis, has been previously suggested. We hypothesized that the immunodominant P. papatasi salivary protein PpSP32 binds to desmogleins 1 and 3 (Dsg1 and Dsg3), triggering loss of tolerance to these pemphigus target autoantigens. Here, we show using far-Western blot that the recombinant PpSP32 protein (rPpSP32) binds to epidermal proteins with a MW of approximately 170 kDa. Coimmunoprecipitation revealed the interaction of rPpSP32 with either Dsg1 or Dsg3. A specific interaction between PpSP32 and Dsg1 and Dsg3 was further demonstrated by ELISA assays. Finally, mice immunized with rPpSP32 twice per week exhibited significantly increased levels of anti-Dsg1 and -Dsg3 antibodies from day 75 to 120. Such antibodies were specific for Dsg1 and Dsg3 and were not the result of cross-reactivity to PpSP32. In this study, we demonstrated for the first time to our knowledge a specific binding between PpSP32 and Dsg1 and Dsg3, which might underlie the triggering of anti-Dsg antibodies in patients exposed to sand fly bites. We also confirmed the development of specific anti-Dsg1 and -Dsg3 antibodies in vivo after PpSP32 immunization in mice. Collectively, our results provide evidence that environmental factors, such as the exposure to P. papatasi bites, can trigger the development of autoimmune antibodies.
此前曾有人提出，突尼斯地方性天疱疮的发病与动物源性皮肤利什曼病的传播媒介巴氏白蛉叮咬之间可能存在病因学联系。我们推测，免疫显性的巴氏白蛉唾液蛋白PpSP32与桥粒芯糖蛋白1和3（Dsg1和Dsg3）结合，引发对这些天疱疮靶自身抗原的耐受性丧失。在此，我们通过Far-Western印迹法表明，重组PpSP32蛋白（rPpSP32）与分子量约为170 kDa的表皮蛋白结合。免疫共沉淀揭示了rPpSP32与Dsg1或Dsg3的相互作用。ELISA分析进一步证明了PpSP32与Dsg1和Dsg3之间存在特异性相互作用。最后，每周用rPpSP32免疫两次的小鼠从第75天到120天抗Dsg1和抗Dsg3抗体水平显著升高。此类抗体对Dsg1和Dsg3具有特异性，并非与PpSP32交叉反应的结果。在本研究中，据我们所知首次证明了PpSP32与Dsg1和Dsg3之间存在特异性结合，这可能是接触白蛉叮咬的患者中抗Dsg抗体触发的基础。我们还证实了在小鼠中用PpSP32免疫后体内会产生特异性抗Dsg1和抗Dsg3抗体。总体而言，我们的结果提供了证据表明环境因素，如接触巴氏白蛉叮咬，可触发自身免疫抗体的产生。
