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Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
Published on: January 17, 2014
Intranasal Cry1Ac protoxin is an effective mucosal and systemic carrier and adjuvant of Streptococcus pneumoniae
L Moreno-Fierros1, E J Ruiz-Medina, R Esquivel
1UBIPRO Inmunidad en Mucosas, FES-Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla, México. lemofi@servidor.unam.mx
Insights
The recombinant Cry1Ac protoxin from Bacillus thuringiensis enhances immune responses to Streptococcus pneumoniae polysaccharides. This finding may improve mucosal vaccine design for infants and children.
Area of Science:
- Immunology
- Vaccinology
- Microbial Pathogenesis
Background:
- Streptococcus pneumoniae poses a significant respiratory threat, particularly to vulnerable populations like infants and the elderly.
- Current parenteral vaccines are limited in efficacy for infants due to poor immunogenicity of capsular polysaccharides (CPSs).
- Developing effective mucosal vaccines is hindered by the need for safe and potent adjuvants or carriers.
Purpose of the Study:
- To evaluate the Cry1Ac protoxin from Bacillus thuringiensis as a carrier and adjuvant for Streptococcus pneumoniae CPS.
- To assess the induction of mucosal and systemic antibody responses following intranasal and intraperitoneal immunization in mice.
Main Methods:
- Mice were immunized intranasally and intraperitoneally with S. pneumoniae CPS, either alone, coadministered with Cry1Ac, or conjugated to Cry1Ac.
- Systemic and mucosal specific antibody responses were measured.
Main Results:
- Intranasal administration of S. pneumoniae CPS with Cry1Ac (either coadministered or conjugated) significantly enhanced both systemic and mucosal antibody responses compared to CPS alone.
- Cry1Ac demonstrated adjuvant effects on pneumococcal polysaccharides.
Conclusions:
- The recombinant Cry1Ac protoxin shows promise as a carrier and adjuvant for developing more effective pneumococcal vaccines, particularly for mucosal delivery.
- Cry1Ac's adjuvant properties could be beneficial in overcoming the immunogenicity challenges associated with polysaccharide-based vaccines in young children.
Abstract:
Streptococcus pneumoniae is a major respiratory pathogen in infants, children and the elderly. Available parenteral anti-pneumococcal vaccines based on type-specific capsular polysaccharides (CPSs) are useful in adults but do not elicit protective immunity in infants and young children. To enhance their immunogenicity, pneumococcal CPSs conjugated to proteins are being developed. Mucosal vaccines may induce mucosal and systemic immune responses, but their development has been hampered by the lack of effective, inexpensive innocuous mucosal adjuvants or immunogenic vaccine carriers. We have demonstrated that the recombinant Cry1Ac protoxin from Bacillus thuringiensis is highly immunogenic and has mucosal and systemic adjuvant effects on proteins coadministered in mice. In this work, we evaluated Cry1Ac as a carrier and adjuvant of S. pneumoniae CPS for the induction of mucosal and systemic antibody responses after intranasal and intraperitoneal immunization in mice. Our results demonstrate that intranasal application of pneumococcal polysaccharides either coadministered or conjugated with Cry1Ac induces higher systemic and mucosal specific antibody responses than those elicited by pneumococcal polysaccharides alone. Adjuvant effects of Cry1Ac on polysaccharides may be appropriate for vaccine design.
