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Updated: Mar 1, 2026
Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice
Published on: February 22, 2019
Small protein A and phospholipase D immunization serves a protective role in a mouse pneumonia model of
Haitao Li1, Hongyi Tan1, Yongbin Hu2
1Department of Pulmonary and Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
Abstract:
Acinetobacter baumannii is an important pathogen that primarily causes hospital-acquired pneumonia. The present study sought to investigate whether small protein A (SmpA) and phospholipase D (PLD) are potential candidates for protective immunity against infection with A. baumannii. Mice immunized with the fusion proteins histidine (His)‑SmpA and His‑PLD exhibited a specific immunoglobulin G response. In a pneumonia model, active and passive immunization against SmpA and PLD protected mice from A. baumannii infection. The protection was demonstrated by a markedly improved survival rate, and reduced pulmonary bacterial load, infiltration and cytokine levels in the broncho‑alveolar lavage fluid and the serum, although a combination of the two antigens did not provide improved protection compared with immunization with the individual antigens alone. In conclusion, it was identified that SmpA and PLD are highly immunogenic proteins, and potential antigen candidates for the development of effective vaccines or to prepare antisera to mitigate A. baumannii infection.
Insights
Small protein A (SmpA) and phospholipase D (PLD) from Acinetobacter baumannii show promise as vaccine candidates. Immunization with SmpA or PLD improved survival and reduced infection severity in mice.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Acinetobacter baumannii is a significant cause of hospital-acquired pneumonia.
- Effective vaccines and treatments against A. baumannii infections are urgently needed.
Purpose of the Study:
- To evaluate small protein A (SmpA) and phospholipase D (PLD) as potential vaccine candidates against A. baumannii.
- To assess the immunogenicity and protective efficacy of SmpA and PLD in a mouse model.
Main Methods:
- Mice were immunized with fusion proteins containing histidine (His)-SmpA and His-PLD.
- Immune responses were measured by immunoglobulin G (IgG) levels.
- Efficacy was tested in a pneumonia model, assessing survival rates, bacterial load, and inflammatory markers.
Main Results:
- Immunization with His-SmpA and His-PLD elicited specific IgG responses.
- Both active and passive immunization with SmpA and PLD demonstrated protection against A. baumannii infection.
- Protected mice showed increased survival, reduced bacterial load, and lower levels of inflammatory cytokines.
Conclusions:
- SmpA and PLD are highly immunogenic proteins.
- These proteins are promising candidates for developing vaccines or antisera against A. baumannii infections.
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