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Oral Immunization with YncE-Encapsulated Chitosan Nanoparticles Confers Protective Immunity against Enterotoxigenic
Fatemeh Mahmoodi Lamooki1, Farajollah Shahriari Ahmadi2, Rouhollah Kazemi3
1School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Insights
A novel nanovaccine using the YncE protein in chitosan nanoparticles shows promise for preventing enterotoxigenic Escherichia coli (ETEC) infections. This ETEC vaccine candidate successfully protected mice, highlighting its potential for future development.
Area of Science:
- Microbiology
- Immunology
- Nanotechnology
Background:
- Gastrointestinal diseases, particularly diarrhea, affect millions globally, with children under five being most vulnerable.
- Enterotoxigenic Escherichia coli (ETEC) is a primary cause of severe diarrhea, leading to malnutrition and mortality in young children.
- ETEC pathogenesis involves bacterial adhesion via colonization factors and toxin production (ST, LT), causing diarrheal illness.
Purpose of the Study:
- To evaluate the potential of recombinant surface protein YncE, encapsulated in chitosan nanoparticles, as a novel vaccine candidate against ETEC.
- To assess the immunogenicity and protective efficacy of the YncE-based nanovaccine in a mouse model.
Main Methods:
- The recombinant YncE gene was cloned, expressed, and purified, with confirmation via Western blot.
- Purified YncE was encapsulated in chitosan nanoparticles; particle size was measured.
- BALB/c mice were immunized via injection, oral administration, or a combined regimen, with a control group.
- Immunogenicity was assessed by measuring antibody titers (ELISA), and protective efficacy was determined through a bacterial challenge assay.
Main Results:
- Chitosan nanoparticles successfully encapsulated the recombinant YncE protein.
- Immunization with YncE-loaded nanoparticles induced significant humoral and mucosal immune responses.
- Mice immunized with the YncE nanovaccine demonstrated protective immunity against ETEC challenge.
Conclusions:
- The YncE protein, when formulated in chitosan nanoparticles, confers protection against ETEC infection in mice.
- This YncE-based nanovaccine represents a promising candidate for the development of effective ETEC vaccines.
Background:
Every year, a large number of people worldwide suffer from gastrointestinal diseases such as diarrhea. Among this population, children under five are particularly vulnerable and are at increased risk of death or malnutrition. Enterotoxigenic Escherichia coli (ETEC) is a major cause of this severe diarrhea. The bacteria first adhere to intestinal cells using colonization factors (CFs), then produce heat-stable (ST) and heat-labile (LT) toxins, which together are responsible for causing the severe diarrheal illness.
Objective:
to investigate the potential of the recombinant surface protein YncE, encapsulated within chitosan nanoparticles, as a novel vaccine candidate, and to evaluate its immunogenicity.
Methods:
The recombinant YncE gene, encoding the surface protein YncE, was cloned, expressed, purified. Successful expression and purification were confirmed via Western blot analysis. The purified recombinant protein was subsequently encapsulated within chitosan nanoparticles, and the particle size was measured. BALB/c mice were divided into five groups: recombinant protein injection, nanoparticle injection, oral nanoparticle administration, combined oral-injection nanoparticle regimen, and control. Immunogenicity was evaluated by measuring antibody titers using an enzyme-linked immunosorbent assay (ELISA). Finally, a bacterial challenge assay was conducted on all immunized groups to evaluate protective efficacy.
Results:
Following expression and purification, the size of the YncE-containing nanoparticles was measured. These nanoparticles successfully induced both humoral and mucosal immune responses. Furthermore, immunized mice challenged with the YncE-containing chitosan nanovaccine demonstrated protective immunity against ETEC.
Conclusion:
Taken together, our results show that the YncE protein-when packaged in chitosan nanoparticles-protects mice against ETEC infection. This makes YncE a strong candidate for future vaccine development.
