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Updated: Mar 2, 2026
Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
Published on: January 17, 2014
Systemic and mucosal immune responses elicited by intranasal immunization with a pneumococcal bacterium-like
Jingcai Lu1, Hongjia Hou2, Dandan Wang2
1National Engineering Laboratory for AIDS Vaccine, School of Life Science, Jilin University, Changchun 130012, China; Changchun BCHT Biotechnology Co., Changchun 130012, China.
Abstract:
Pneumolysin (Ply) is an important virulence factor in pneumococcal infection and a conserved cholesterol-binding cytotoxin expressed by all serotypes of Streptococcus pneumoniae. We previously developed a highly detoxified Ply mutant designated Plym2 by replacement of two amino acids (C428G and W433F), which lost cytotoxicity but retained the ability to induce neutralizing antibodies. In the present work, we applied bacterium-like particles (BLPs) as a carrier and immunostimulant for the development of a Plym2 intranasal vaccine, in which the Plym2 protein was displayed on the surface of BLPs. Intranasal immunization of mice with BLP-Plym2 not only induced a high level of serum IgG antibodies but also a high level of mucosal SIgA antibodies in lung lavages. Antiserum induced by the BLP-Plym2 vaccine elicited high-titer neutralization activity which could inhibit the hemolysis of wild-type Ply. In conclusion, the BLP-Plym2 vaccine was demonstrated to be a promising strategy for intranasal immunization to enhance both systemic and mucosal immune responses.
Insights
A new intranasal vaccine using bacterium-like particles (BLPs) carrying a detoxified pneumolysin (Plym2) effectively stimulates both systemic and mucosal immunity against pneumococcal infections.
Area of Science:
- Immunology
- Vaccinology
- Microbiology
Background:
- Pneumolysin (Ply) is a key virulence factor in Streptococcus pneumoniae infections.
- A detoxified Ply mutant (Plym2) retains immunogenicity without cytotoxicity.
- Developing effective intranasal vaccines is crucial for combating pneumococcal diseases.
Purpose of the Study:
- To develop and evaluate an intranasal vaccine using bacterium-like particles (BLPs) displaying Plym2.
- To assess the immunogenicity and efficacy of the BLP-Plym2 vaccine in a mouse model.
Main Methods:
- Plym2 protein was displayed on the surface of BLPs.
- Mice were immunized intranasally with the BLP-Plym2 vaccine.
- Serum IgG and mucosal SIgA antibody levels were measured.
- Neutralization activity against wild-type Ply was assessed.
Main Results:
- Intranasal BLP-Plym2 immunization induced high levels of serum IgG antibodies.
- Significant mucosal SIgA antibodies were detected in lung lavages.
- Vaccine-induced antiserum demonstrated high-titer neutralization activity against Ply hemolysis.
Conclusions:
- The BLP-Plym2 vaccine is a promising intranasal strategy for enhancing systemic and mucosal immunity.
- This approach offers a potential new avenue for pneumococcal disease prevention.
- Further development could lead to a novel vaccine for Streptococcus pneumoniae.
