C-Terminal Clostridium perfringens Enterotoxin-Mediated Antigen Delivery for Nasal Pneumococcal Vaccine

Abstract

Efficient vaccine delivery to mucosal tissues including mucosa-associated lymphoid tissues is essential for the development of mucosal vaccine. We previously reported that claudin-4 was highly expressed on the epithelium of nasopharynx-associated lymphoid tissue (NALT) and thus claudin-4-targeting using C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE) effectively delivered fused antigen to NALT and consequently induced antigen-specific immune responses. In this study, we applied the C-CPE-based vaccine delivery system to develop a nasal pneumococcal vaccine. We fused C-CPE with pneumococcal surface protein A (PspA), an important antigen for the induction of protective immunity against Streptococcus pneumoniae infection, (PspA-C-CPE). PspA-C-CPE binds to claudin-4 and thus efficiently attaches to NALT epithelium, including antigen-sampling M cells. Nasal immunization with PspA-C-CPE induced PspA-specific IgG in the serum and bronchoalveolar lavage fluid (BALF) as well as IgA in the nasal wash and BALF. These immune responses were sufficient to protect against pneumococcal infection. These results suggest that C-CPE is an efficient vaccine delivery system for the development of nasal vaccines against pneumococcal infection.

Cationic pullulan nanogel as a safe and effective nasal vaccine delivery system for respiratory infectious diseases

“…26 Furthermore, an antigen-delivery method has been developed that targets claudin-4, a major cell-adhesion molecule in tight junctions that is highly expressed on the epithelium of nasopharynx-associated lymphoid tissue. 27 PspA–C-CPE, a fusion protein comprising PspA and a C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), which binds claudin-4, efficiently attached to nasopharynx-associated lymphoid epithelium after nasal administration to mice. 27 In addition, PspA–C-CPE effectively induced antigen-specific immune responses, and PspA-specific antibodies were elevated not only as IgG in the serum and bronchoalveolar lavage fluid but also as IgA in nasal washes and bronchoalveolar lavage fluid.…”

“…27 PspA–C-CPE, a fusion protein comprising PspA and a C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), which binds claudin-4, efficiently attached to nasopharynx-associated lymphoid epithelium after nasal administration to mice. 27 In addition, PspA–C-CPE effectively induced antigen-specific immune responses, and PspA-specific antibodies were elevated not only as IgG in the serum and bronchoalveolar lavage fluid but also as IgA in nasal washes and bronchoalveolar lavage fluid. Consequently, mice nasally vaccinated with PspA–C-CPE were protected against pneumococcal infection.…”

“…Consequently, mice nasally vaccinated with PspA–C-CPE were protected against pneumococcal infection. 27 In addition, nasal immunization of PspA with mucosal adjuvants, such as a plasmid-expressed Flt3 ligand and CpG oligodeoxynucleotides, yielded PspA-specific SIgA in aged or pregnant mice. 28 After nasal vaccination, bacterial colonization was inhibited even in 2-year-old (that is, aged) mice and in pups born to vaccinated dams.…”

The interaction of Clostridium perfringens enterotoxin with receptor claudins

“…Given the critical role of M cells in mucosal immunity, targeting ligands to M cells is an attractive strategy for improving mucosal immunizations. Interestingly, M cells show significant expression of claudin-4, a strong CPE receptor [63]. While fusion proteins containing active CPE cannot be used for immunizations due to toxicity issues, the presence of claudin-4 on M cells suggested that a targeting strategy using nontoxic, but claudin binding-capable, CPE derivatives might be useful for preparing fusion proteins for use in improved mucosal vaccines.…”

“…Several published studies now support this approach. For example, C-CPE has been fused with pneumococcal surface protein A (PspA), an important antigen for inducing protective immunity against Streptococcus pneumoniae infection [63]. When administered intranasally, this vaccine induced immune responses that were protective against infection by this important bacterial pathogen.…”