Antigen Epitope Developed Based on Acinetobacter baumannii MacB Protein Can Provide Partial Immune Protection in Mice
Xiaojie Song1, Guanghui Zhao2, Meiling Ding1
1Department of Respiratory Medicine, Qilu Hospital of Shandong University, Qingdao, China.
Abstract:
Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen widely present in medical environment. Given its complex drug resistance, A. baumannii poses a serious threat to the safety of critically ill patients. Given the limited alternative antibiotics, nonantibiotic-based functional anti-A. baumannii infection proteins must be developed. In this study, we firstly used a series of biological software to predict potential epitopes in the MacB protein sequence and verified them by antibody recognition and lymphocyte proliferation tests. We finally screened out B cell epitope 2, CD8+ T cell epitope 7, and CD4+ T cell epitope 11 and connected them to construct a recombinant antigen epitope (RAE). The determination of IgG in the serum of immunised mice and cytokines in the supernatant of lymphocytes showed that the constructed epitope induced an immune response mediated by Th-1 cells. Finally, the challenge experiment of A. baumannii infection in mice confirmed that the epitope developed based on MacB, especially RAE, provided incomplete immune protection for mice.
Insights
Developing nonantibiotic treatments for Acinetobacter baumannii infections is crucial. This study created a recombinant antigen epitope (RAE) from the MacB protein, which induced an immune response and offered partial protection against A. baumannii in mice.
Area of Science:
- Microbiology
- Immunology
- Drug Discovery
Background:
- Acinetobacter baumannii is a significant opportunistic pathogen causing severe infections, particularly in critical care settings.
- High levels of drug resistance in A. baumannii necessitate the development of novel, nonantibiotic therapeutic strategies.
- The MacB protein is explored as a potential target for anti-A. baumannii interventions.
Purpose of the Study:
- To predict and validate functional epitopes from the MacB protein sequence.
- To construct a recombinant antigen epitope (RAE) using identified B cell, CD8+ T cell, and CD4+ T cell epitopes.
- To evaluate the immunogenicity and protective efficacy of the RAE against Acinetobacter baumannii infection.
Main Methods:
- Bioinformatics tools were used for epitope prediction from the MacB protein sequence.
- Antibody recognition and lymphocyte proliferation assays validated predicted epitopes.
- Recombinant antigen epitope (RAE) was constructed by linking selected epitopes.
- Immunological assays (IgG, cytokine analysis) and mouse infection challenge models were employed.
Main Results:
- B cell epitope 2, CD8+ T cell epitope 7, and CD4+ T cell epitope 11 were identified and selected.
- The constructed RAE successfully induced a Th-1 cell-mediated immune response in immunized mice.
- RAE demonstrated incomplete but significant immune protection in a mouse model of Acinetobacter baumannii infection.
Conclusions:
- Epitopes derived from the MacB protein can elicit a functional immune response against Acinetobacter baumannii.
- The developed recombinant antigen epitope (RAE) shows promise as a nonantibiotic-based strategy for Acinetobacter baumannii infection.
- Further research is warranted to enhance the protective efficacy of RAE for clinical application.
