Mucosal immunity of mannose-modified chitosan microspheres loaded with the nontyepable Haemophilus influenzae outer membrane protein P6 in BALB/c mice

• Published in: PloS one Vol. 17; no. 6; p. e0269153
• Main Authors: Ma, Yushuai, Zhao, Ying, Chen, Rui, Sun, Wanru, Zhang, Yanxia, Qiao, Haixia, Chang, Yueli, Kang, Shaoping, Zhang, Yutuo
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.06.2022; Public Library of Science (PLoS)
• Subjects: Amination; Amino acids; Antibiotics; Antigen presentation; Antigens; Bacterial proteins; Biology and Life Sciences; Care and treatment; CD4 antigen; CD8 antigen; Cell-mediated immunity; Chitin; Chitosan; Chronic obstructive pulmonary disease; Cytotoxicity; Drug delivery systems; Drugs; E coli; Ear diseases; Experiments; Haemophilus influenzae; Health aspects; Helper cells; Hemophilus infections; Immune response; Immune response (humoral); Immune system; Immunity; Immunization; Infections; Laboratory animals; Lung diseases; Lymphocytes; Lymphocytes T; Major histocompatibility complex; Mannose; Medicine and Health Sciences; Membrane proteins; Membranes; Microspheres; Morbidity; Mucosal immunity; Nasopharynx; Obstructive lung disease; Opportunist infection; Otitis media; Pathogens; Pharmaceutical research; Physical Sciences; Pneumonia; Protein P6; Proteins; Respiratory tract infections; Sodium; Toxicity; Tripolyphosphate; Vaccines; Vehicles; China; Beijing China; Sweden; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0269153

Nontypeable Haemophilus influenzae (NTHi) is a common opportunistic pathogen that colonizes the nasopharynx. NTHi infections result in enormous global morbidity in two clinical settings: otitis media in children and acute exacerbation of chronic obstructive pulmonary disease (COPD) in adults. Thus, there is an urgent need to design and develop effective vaccines to prevent morbidity and reduce antibiotic use. The NTHi outer membrane protein P6, a potential vaccine candidate, is highly conserved and effectively induces protective immunity. Here, to enhance mucosal immune responses, P6-loaded mannose-modified chitosan (MC) microspheres (P6-MCMs) were developed for mucosal delivery. MC (18.75%) was synthesized by the reductive amination reaction method using sodium cyanoborohydride (NaBH 3 CN), and P6-MCMs with an average size of 590.4±16.2 nm were successfully prepared via the tripolyphosphate (TPP) ionotropic gelation process. After intranasal immunization with P6-MCMs, evaluation of humoral immune responses indicated that P6-MCMs enhance both systemic and mucosal immune responses. Evaluation of cellular immune responses indicated that P6-MCMs enhance cellular immunity and trigger a mixed Th1/Th2-type immune response. Importantly, P6-MCMs also trigger a Th17-type immune response. They are effective in promoting lymphocyte proliferation and differentiation without toxicity in vitro. The results also demonstrate that P6-MCMs can effectively induce MHC class I- and II-restricted cross-presentation, promoting CD4 + -mediated Th immune responses and CD8 + -mediated cytotoxic T lymphocyte (CTL) immune responses. Evaluation of protective immunity indicated that immunization with P6-MCMs can reduce inflammation in the nasal mucosa and the lung and prevent NTHi infection. In conclusion, MCMs are a promising adjuvant-delivery system for vaccines against NTHi.