Related Experiment Video
Updated: Apr 28, 2026
Protective Efficacy and Pulmonary Immune Response Following Subcutaneous and Intranasal BCG Administration in Mice
Published on: September 19, 2016
Three-Component Subunit Vaccine Induces Protective Immunity Against Mycoplasma pneumoniae in Mice
Han Wang1, Tiantian Wang1, Zhuoran Hou1,2
1National Key Laboratory of Advanced Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
Background:
Mycoplasma pneumoniae (MP) is a major cause of respiratory tract infections in children and adolescents. Currently, there is no licensed vaccine, underscoring the urgent need for the development of safe and effective vaccines.
Objective:
The aim of this study is to develop a recombinant subunit vaccine candidate incorporating three antigens: the P1 protein, the P40/90 complex, and a detoxified mutant of community-acquired respiratory distress syndrome toxin. The protective efficacy of this vaccine candidate was also evaluated.
Methods:
Target genes were codon-optimized for expression in E. coli, and the recombinant proteins were successfully expressed and purified. The low-toxicity CARDS toxin mutant was screened based on TNF-α secretion levels in stimulated RAW264.7 cells. A three-component vaccine composed of P1, P40/90, and the mutant CARDS toxin was formulated and adjuvanted with either Al(OH)3 alone or in combination with CpG. Mice were immunized, and immunogenicity was assessed by measuring antigen-specific IgG antibody titers. Protective efficacy was evaluated following challenge by analyzing lung histopathology, bacterial load, and inflammatory cytokine levels.
Results:
Seven high-purity recombinant proteins were successfully produced, including P1, the P40/90 complex, wild-type CARDS toxin, and four CARDS toxin mutants (E132A, E132Q, H36A, R10A). The E132A mutant was selected due to its significantly reduced toxicity while retaining immunogenicity. The three-component vaccine effectively elicited antibody responses against each of the included antigens. After three immunizations, IgG antibody titers in all groups reached approximately 104. Immunized mice showed markedly reduced pulmonary pathology scores (control group: 2 or 2.67; immunized groups: 1.67, 1.33, and 0) and significantly decreased bacterial loads in lung tissue (control: 30.11 ± 10.40 cp/μL; immunized groups: 20.72 ± 4.37 cp/μL and 8.51 ± 8.32 cp/μL). Furthermore, the group receiving the alum + CpG adjuvant exhibited approximately a 10-fold higher antibody response compared with the alum-only group, indicating enhanced protective efficacy.
Conclusions:
The three-component candidate vaccine, MPtriV, adjuvanted with Al(OH)3 + CpG, demonstrates promising immunogenicity, safety, and protective efficacy against Mycoplasma pneumoniae infection, providing a viable strategy and experimental foundation for the development of MP subunit vaccines.
Insights
A new three-component vaccine candidate, MPtriV, shows promise for preventing Mycoplasma pneumoniae infections. This recombinant subunit vaccine, combining P1, P40/90, and a detoxified CARDS toxin mutant, demonstrated strong immunogenicity and protective efficacy in mice.
Area of Science:
- Vaccinology
- Microbiology
- Immunology
Background:
- Mycoplasma pneumoniae (MP) is a significant cause of pediatric respiratory infections.
- Current lack of a licensed MP vaccine highlights the need for effective vaccine development.
Purpose of the Study:
- To develop a recombinant subunit vaccine candidate against Mycoplasma pneumoniae.
- To evaluate the protective efficacy of a novel three-component vaccine (MPtriV).
Main Methods:
- Developed a three-component vaccine using P1, P40/90, and a low-toxicity CARDS toxin mutant.
- Expressed and purified recombinant antigens in E. coli.
- Assessed immunogenicity and protective efficacy in a mouse model using Al(OH)3 and CpG adjuvants.
Main Results:
- Successfully produced high-purity recombinant proteins and selected an immunogenic, low-toxicity CARDS toxin mutant (E132A).
- The MPtriV vaccine elicited robust antigen-specific IgG antibody responses (approx. 10^4).
- Vaccination significantly reduced lung pathology and bacterial load, with Al(OH)3 + CpG adjuvant showing enhanced efficacy.
Conclusions:
- The MPtriV vaccine candidate, particularly with Al(OH)3 + CpG adjuvant, demonstrates significant immunogenicity, safety, and protective potential.
- This study provides a strong foundation for developing MP subunit vaccines.
