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Zuo Z, Zou Y, Li Q, Guo Y, Zhang T, Wu J, He C, Eko FO. Intranasal immunization with inactivated chlamydial elementary bodies formulated in VCG-chitosan nanoparticles induces robust immunity against intranasal Chlamydia psittaci challenge. Sci Rep 2021; 11:10389. [PMID: 34001988 PMCID: PMC8129140 DOI: 10.1038/s41598-021-89940-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 05/04/2021] [Indexed: 02/03/2023] Open
Abstract
Vaccines based on live attenuated Chlamydia elementary bodies (EBs) can cause disease in vaccinated animals and the comparably safer inactivated whole EBs are only marginally protective. Recent studies show that a vaccine formulation comprising UV-inactivated EBs (EB) and appropriate mucosal delivery systems and/or adjuvants induced significant protective immunity. We tested the hypothesis that intranasal delivery of UV-inactivated C. psittaci EB formulated in Vibrio cholerae ghosts (VCG)-chitosan nanoparticles will induce protective immunity against intranasal challenge in SPF chickens. We first compared the impact of VCG and CpG adjuvants on protective immunity following IN mucosal and IM systemic delivery of EB formulated in chitosan hydrogel/microspheres. Immunologic analysis revealed that IN immunization in the presence of VCG induced higher levels of IFN-γ response than IM delivery or the CpG adjuvanted groups. Also, vaccine efficacy evaluation showed enhanced pharyngeal bacterial clearance and protection against lung lesions with the VCG adjuvanted vaccine formulation, thereby establishing the superior adjuvanticity of VCG over CpG. We next evaluated the impact of different concentrations of VCG on protective immunity following IN mucosal immunization. Interestingly, the adjuvanticity of VCG was concentration-dependent, since protective immunity induced following IN mucosal immunization showed dose-dependent immune responses and protection. These studies reveal that formulation of inactivated chlamydial antigens with adjuvants, such as VCG and chitosan increases their ability to induce protective immune responses against challenge.
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Affiliation(s)
- Zonghui Zuo
- grid.22935.3f0000 0004 0530 8290Key Lab of Animal Epidemiology and Zoonosis, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 People’s Republic of China
| | - Yongjuan Zou
- grid.9227.e0000000119573309Key Laboratory of Biopharmaceutical Production and Formulation Engineering, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Qiang Li
- grid.22935.3f0000 0004 0530 8290Key Lab of Animal Epidemiology and Zoonosis, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 People’s Republic of China
| | - Yongxia Guo
- grid.22935.3f0000 0004 0530 8290Key Lab of Animal Epidemiology and Zoonosis, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 People’s Republic of China
| | - Tianyuan Zhang
- grid.22935.3f0000 0004 0530 8290Key Lab of Animal Epidemiology and Zoonosis, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 People’s Republic of China
| | - Jie Wu
- grid.9227.e0000000119573309Key Laboratory of Biopharmaceutical Production and Formulation Engineering, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Cheng He
- grid.22935.3f0000 0004 0530 8290Key Lab of Animal Epidemiology and Zoonosis, College of Veterinary Medicine, China Agricultural University, Beijing, 100193 People’s Republic of China
| | - Francis O. Eko
- grid.9001.80000 0001 2228 775XDepartment of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310 USA
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