Mucosal immunization with helicobacter, CpG DNA, and cholera toxin is protective

Area of Science:

• Immunology
• Vaccinology
• Microbiology

Background:

• Mucosal antigen delivery necessitates effective adjuvants for robust mucosal immunity.
• Cholera toxin (CT) and E. coli heat-labile toxin are established mucosal adjuvants.
• Unmethylated CpG immunostimulatory oligodeoxynucleotides (ODNs) are emerging as potential mucosal adjuvants.

Purpose of the Study:

• To evaluate the efficacy of CpG ODNs as a mucosal adjuvant, alone and in combination with CT.
• To assess the induction of mucosal immune responses against Helicobacter felis.
• To determine the protective efficacy and synergistic effects of CpG ODN and CT in a mouse model.

Main Methods:

• Mice were immunized with sonicated H. felis with or without CT and/or CpG ODN adjuvants.
• Serum IgG and fecal IgA anti-H. felis antibody responses were measured.
• Protection against H. felis challenge was assessed, including bacterial colonization via quantitative PCR.

Main Results:

• Both CT and CpG ODN adjuvants increased serum anti-H. felis IgG.
• Specific fecal anti-H. felis IgA responses were induced by either adjuvant or their combination.
• Intranasal administration of H. felis with both CT and CpG ODN resulted in the highest IgA levels.
• CT alone provided significant protection against H. felis challenge.
• The combination of CpG ODN and CT delivered intranasally induced sterile immunity, with no detectable bacterial colonization.

Conclusions:

• CpG ODNs can enhance mucosal immune responses when combined with CT.
• The combination of CpG ODN and CT demonstrates synergistic effects for inducing protective mucosal immunity.
• Intranasal delivery of H. felis vaccine with CpG ODN and CT offers a promising strategy for achieving sterile immunity.