Related Experiment Video
Updated: Dec 17, 2025
Protective Efficacy and Pulmonary Immune Response Following Subcutaneous and Intranasal BCG Administration in Mice
Published on: September 19, 2016
Type I pili, CsuA/B and FimA induce a protective immune response against Acinetobacter baumannii
Fatemeh Ramezanalizadeh1, Parviz Owlia2, Iraj Rasooli3
1Department of Biology, Shahed University, Tehran Iran.
Background:
Acinetobacter baumannii, a nosocomial pathogen, is considered as a common cause of hospital and community-acquired infections. Emerging multidrug-resistance in this pathogen followed by subsequent problems in treatment has been increasing to alarming levels that warrant investigation of new therapeutic approaches. One strategy to reduce antibiotic resistance is to use of vaccines. Although there is no vaccine currently in development for this pathogen, different attempts have been made to develop one.
Methods:
In this study, we used two different recombinant pilus proteins (CsuA/B and FimA) either singly or in combination to evaluate protective efficacy against A. baumannii in lethal and sub-lethal murine sepsis models.
Findings:
Active immunization with recombinant proteins in combination elicited high levels of IgG antibody after the first immunization and provided 62% (five of eight mice; p < 0·001) protection against a lethal dose (1·2 × 106 CFU) of A. baumannii along with efficient clearance of bacteria in internal organs viz. spleen, liver, and lungs at sub-lethal challenge. Immunization with CsuA/B alone conferred partial protection as demonstrated by low survival rate (three [37%] of eight mice; p < 0·05) after lethal challenge and reduction of bacteria in internal organs of the mice after 24 h post-sub-lethal infection. Immunization with FimA, in comparison to CsuA/B, showed better protection (four [50%] of eight mice; p < 0·01) and reduction in CFU after 14 h.
Interpretation:
Our results showed that pilus proteins in combination as a single immunogen could potentially impart protection against A. baumannii.
Funding:
Shahed University.
Insights
Developing a vaccine against Acinetobacter baumannii is crucial due to rising antibiotic resistance. This study shows that combining pilus proteins CsuA/B and FimA as a single immunogen offers significant protection against A. baumannii infections in mice.
Area of Science:
- * Microbiology
- * Immunology
- * Vaccinology
Background:
- * Acinetobacter baumannii is a significant nosocomial pathogen causing severe infections.
- * Increasing multidrug-resistance necessitates novel therapeutic strategies, including vaccines.
- * Current vaccine development for A. baumannii is limited, highlighting the need for research.
Purpose of the Study:
- * To evaluate the protective efficacy of recombinant pilus proteins (CsuA/B and FimA) against Acinetobacter baumannii.
- * To assess the potential of these proteins, individually or in combination, as vaccine candidates.
Main Methods:
- * Two recombinant pilus proteins, CsuA/B and FimA, were used for active immunization in murine models.
- * Mice were challenged with lethal and sub-lethal doses of A. baumannii to assess protection.
- * Bacterial load in internal organs and survival rates were measured post-immunization and challenge.
Main Results:
- * Combined immunization with CsuA/B and FimA provided 62% protection against lethal A. baumannii challenge and reduced bacterial load in organs.
- * Single immunization with CsuA/B offered partial protection (37% survival), while FimA showed better efficacy (50% survival).
- * High IgG antibody levels were observed after initial immunization with the combined proteins.
Conclusions:
- * Recombinant pilus proteins, particularly in combination, show promise as a single immunogen for protecting against Acinetobacter baumannii.
- * This approach could be a viable strategy to combat infections caused by this multidrug-resistant pathogen.
Related Concept Videos
01:28Fimbriae, Pili, and Axial Filaments
01:23Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...