Volume 16, Issue 63 (8-2026)
NCMBJ 2026, 16(63): 38-54 |
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Kazemi Afarmjani S, Amani J, Taj Bakhsh E, Zare Karizi S. Comparison of Antibody Titers Against Outer Membrane Protein SlyB and Nano SlyB from Enterotoxigenic Escherichia Coli in Its Pure and Encapsulated Forms in a Model Organism. NCMBJ 2026; 16 (63) :38-54
URL: http://ncmbjpiau.ir/article-1-1851-en.html
URL: http://ncmbjpiau.ir/article-1-1851-en.html
Applied Microbiology Research Center, Biomedicine Technologies Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Abstract: (8 Views)
Extended Abstract
Background and Aim:Gastrointestinal infectious diseases are a major global health concern, particularly in developing countries. Enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of acute diarrhea and associated mortality. Given the widespread prevalence and therapeutic limitations of this infection, the development of effective preventive strategies such as vaccination is essential. Previous studies have shown that primary infection with this bacterium can induce immunity against subsequent infections. This study aimed to design and evaluate SlyB protein-based vaccines that are resistant to the acidic conditions of the stomach and intestinal environment. To enhance bioavailability, colloidal nanocarriers (chitosan nanoparticles) were used.
Materials and Methods:The SlyB gene was isolated from ETEC, analyzed bioinformatically (BLASTn, SignalP, Oligo7, CAI, GC%), cloned into pET28a vector, and expressed in E. coli BL21(DE3). The recombinant protein was purified by Ni-NTA chromatography and encapsulated in chitosan nanoparticles via ionic gelation. Nanoparticle properties were characterized using Malvern Zetasizer (size: 116.6 nm, zeta potential: 19.6 mV). New Zealand rabbits were immunized in six groups (injection, oral, and combined regimens) with 150–300 μg doses. Serum and mucosal IgG and IgA titers were measured by indirect ELISA. The rabbit ileal loop assay was performed to evaluate LT toxin neutralization. Data were analyzed using SPSS software (p < 0.05).
Results:The encapsulation efficiency was 88%. The nano-vaccine induced significantly stronger humoral and mucosal immune responses compared to the pure protein. In the challenge test, a significant reduction in fluid accumulation was observed in the nano-encapsulated groups (p < 0.001).
Conclusion:The results confirm the high potential of chitosan nanoparticles containing recombinant SlyB protein for eliciting protective immunity against ETEC infections in the model organism. Therefore, antigen encapsulation in nanoparticles can serve as an effective strategy for enhancing mucosal immunity and developing oral vaccines against ETEC.
Materials and Methods:The SlyB gene was isolated from ETEC, analyzed bioinformatically (BLASTn, SignalP, Oligo7, CAI, GC%), cloned into pET28a vector, and expressed in E. coli BL21(DE3). The recombinant protein was purified by Ni-NTA chromatography and encapsulated in chitosan nanoparticles via ionic gelation. Nanoparticle properties were characterized using Malvern Zetasizer (size: 116.6 nm, zeta potential: 19.6 mV). New Zealand rabbits were immunized in six groups (injection, oral, and combined regimens) with 150–300 μg doses. Serum and mucosal IgG and IgA titers were measured by indirect ELISA. The rabbit ileal loop assay was performed to evaluate LT toxin neutralization. Data were analyzed using SPSS software (p < 0.05).
Results:The encapsulation efficiency was 88%. The nano-vaccine induced significantly stronger humoral and mucosal immune responses compared to the pure protein. In the challenge test, a significant reduction in fluid accumulation was observed in the nano-encapsulated groups (p < 0.001).
Conclusion:The results confirm the high potential of chitosan nanoparticles containing recombinant SlyB protein for eliciting protective immunity against ETEC infections in the model organism. Therefore, antigen encapsulation in nanoparticles can serve as an effective strategy for enhancing mucosal immunity and developing oral vaccines against ETEC.
Type of Study: Research Article |
Subject:
Microbiology
Received: 2026/07/31 | Accepted: 2026/08/1 | Published: 2026/08/1
Received: 2026/07/31 | Accepted: 2026/08/1 | Published: 2026/08/1
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