title: CpG in Combination with an Inhibitor of Notch Signaling Suppresses Formalin-Inactivated Respiratory Syncytial Virus-Enhanced Airway Hyperresponsiveness and Inflammation by Inhibiting Th17 Memory Responses and Promoting Tissue-Resident Memory Cells in Lungs.
abstract: Respiratory syncytial virus (RSV) is the leading cause of childhood hospitalizations. The formalin-inactivated RSV (FI-RSV) vaccine-enhanced respiratory disease (ERD) has been an obstacle to the development of a safe and effective killed RSV vaccine. Agonists of Toll-like receptor (TLR) have been shown to regulate immune responses induced by FI-RSV. Notch signaling plays critical roles during the differentiation and effector function phases of innate and adaptive immune responses. Cross talk between TLR and Notch signaling pathways results in fine-tuning of TLR-triggered innate inflammatory responses. We evaluated the impact of TLR and Notch signaling on ERD in a murine model by administering CpG, an agonist of TLR9, in combination with L685,458, an inhibitor of Notch signaling during FI-RSV immunization. Activation with CpG or deficiency of MyD88-dependent TLR signaling did not alleviate airway inflammation in FI-RSV-immunized mice. Activation or inhibition of Notch signaling with Dll4, one of the Notch ligands, or L685,458 did not suppress FI-RSV-enhanced airway inflammation either. However, the CpG together with L685,458 markedly inhibited FI-RSV-enhanced airway hyperresponsiveness, weight loss, and lung inflammation. Interestingly, CpG plus L685,458 completely inhibited FI-RSV-associated Th17 and Th17-associated proinflammatory chemokine responses in lungs following RSV challenge but not Th1 or Th2, memory responses. In addition, FI-RSV plus CpG plus L685,458 promoted protective CD8+lung tissue-resident memory (TRM) cells. These results indicate that activation of TLR signaling combined with inhibition of Notch signaling prevent FI-RSV ERD, and the mechanism appears to involve suppressing proinflammatory Th17 memory responses and promoting protective TRM in lungs.IMPORTANCERSV is the most important cause of lower respiratory tract infections in infants. The FI-RSV-enhanced respiratory disease (ERD) is a major impediment to the development of a safe and effective killed RSV vaccine. Using adjuvants to regulate innate and adaptive immune responses could be an effective method to prevent ERD. We evaluated the impact of TLR and Notch signaling on ERD by administering CpG, an agonist of TLR9, in combination with L685,458, an inhibitor of Notch signaling, during FI-RSV immunization. The data showed that treatment of TLR or Notch signaling alone did not suppress FI-RSV-enhanced airway inflammation, while CpG plus L685,458 markedly inhibited ERD. The mechanism appears to involve suppressing Th17 memory responses and promoting tissue-resident memory cells. Moreover, these results suggest that regulation of lung immune memory with adjuvant compounds containing more than one immune-stimulatory molecule may be a good strategy to prevent FI-RSV ERD.
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.|Department of Immunology, Xingtai Medical College, Hebei, China.
authors.forename: Hongyong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hai
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yin
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Wenjian
authors.initials: W
authors.lastname: Li
authors.affiliation: Basic Medical College, Hebei Medical University, Hebei, China.
authors.forename: Boyang
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.|Department of Immunology, Xingtai Medical College, Hebei, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.|Department of Immunology, Xingtai Medical College, Hebei, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Immunology, Hebei Medical University, Hebei, China zengruihong88@aliyun.com weilin21@sina.com.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Hebei, China zengruihong88@aliyun.com weilin21@sina.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Wei
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000139:chemically induced; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002219:Carbamates / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D005557:Formaldehyde; D006801:Humans; D007156:Immunologic Memory; D007249:Inflammation; D008168:Lung / Q000276:immunology* / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D051880:Receptors, Notch / Q000378:metabolism*; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology; D022261:Respiratory Syncytial Virus Vaccines / Q000276:immunology; D018113:Respiratory Syncytial Virus, Human / Q000276:immunology; D015398:Signal Transduction; D058504:Th17 Cells / Q000276:immunology*; D051194:Toll-Like Receptor 1 / Q000276:immunology / Q000378:metabolism; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; C408982:CPG-oligonucleotide; D002219:Carbamates; D004151:Dipeptides; C410009:L 685458; D009838:Oligodeoxyribonucleotides; D051880:Receptors, Notch; D022261:Respiratory Syncytial Virus Vaccines; D051194:Toll-Like Receptor 1; D015164:Vaccines, Inactivated; D005557:Formaldehyde
keywords: CpG; FI-RSV-enhanced respiratory disease; Th17; inhibitor of Notch signaling; tissue-resident memory cells