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Helicobacter pylori is the cause of most cases of stomach ulcers and also causes some digestive cancers. The emergence and spread of antibiotic-resistant strains of H. pylori is one of the most important challenges in the treatment of its infections. The present study aims to develop a concanavalin A (ConA) coated chitosan (CS) nanocarrier-based drug delivery for the targeted release of peptides to the site of H. pylori infection. Accordingly, chitosan was used as an encapsulating agent for CM11 peptide delivery by applying ionotropic gelation method. Con-A was used for coating CS nanoparticles to target H. pylori. The CS NPs and ConA-CS NPs were characterized by FTIR, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The MIC of CM11-loaded ConA-CS NPs against H. pylori SS1 strain was analyzed in vitro. In order to evaluate the treatment efficiency in vivo, a gastric infection model of H. pylori SS1 strain was established in mice and histopathological studies and IL-1β cytokine assay were performed. Based on the results, the size frequency for CS NPs and ConA-CS NPs was about 200 and 350 nm, respectively. The prepared CM11-loaded ConA-CS NPs exhibited antibacterial activity against H. pylori SS1 strain with a concentration of 32 µg/ml. The highest healing process was observed in synthesized CM11-loaded ConA-CS NPs treatments and a significant decrease in IL-1β was observed. Our findings highlight the potential of chitosan nanoparticles as a drug delivery vehicle in the treatment of gastric infection model of H. pylori SS1 strain., (© 2023. The Author(s).)

One promising approach to increase protection against infectious diseases is to use adjuvants that can selectively stimulate the immune responses. In this study, multi-epitope antigens associated with LPS loaded chitosan (LLC) as toll-like receptor agonist or mannosylated chitosan nanoparticle (MCN) as vaccine delivery system were evaluated for their ability to stimulate immune responses to Brucella infection in mice model. Our results indicated that the addition of MCN to our vaccine formulations significantly elicited IFN-γ and IL-2 cytokines and antibody titers, in comparison with the non-adjuvanted vaccine candidates. The present results indicated that multi-epitopes and their administration with LLC or MCN induced Th1 immune response. In addition, vaccine candidates containing MCN provided high percentage of protection against B. melitensis and B. abortus infection. Our results provided support to previous reports indicating that MCNs are attractive adjuvants and addition of this adjuvant to multi-epitopes antigens play an important role in the development of vaccine against Brucella., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Introduction: Vaccine formulation with appropriate adjuvants is an attractive approach to develop protective immunity against pathogens. Calcium phosphate nanoparticles (CaPNs) are considered as ideal adjuvants and delivery systems because of their great potential for enhancing immune responses. In the current study, we have designed nanoparticle-based vaccine candidates to induce immune responses and protection against B. melitensis and B. abortus ., Materials and Methods: For this purpose, we used three Brucella antigens (FliC, 7α-HSDH, BhuA) and two multi-epitopes (poly B and poly T) absorbed by CaPNs. The efficacy of each formulation was evaluated by measuring humoral, cellular and protective responses in immunized mice., Results: The CaPNs showed an average size of about 90 nm with spherical shape and smooth surface. The CaPNs-adsorbed proteins displayed significant increase in cellular and humoral immune responses compared to the control groups. In addition, our results showed increased ratio of specific IgG2a (associated with Th1) to specific IgG1 (associated with Th2). Also, immunized mice with different vaccine candidate formulations were protected against B. melitensis 16M and B. abortus 544, and showed same levels of protection as commercial vaccines ( B. melitensis Rev.1 and B. abortus RB51) except for BhuA-CaPNs., Discussion: Our data support the hypothesis that these antigens absorbed with CaPNs could be effective vaccine candidates against B. melitensis and B. abortus ., Competing Interests: The authors declare no conflicts of interest in this work., (© 2020 Sadeghi et al.)

Brucellosis is a worldwide bacterial zoonosis disease. Live attenuated Brucella vaccines have several drawbacks. Thus development of a safe and effective vaccine for brucellosis is a concern of many scientists. FliC protein contributes in virulence of Brucella; hence, it is a promising target for brucellosis vaccine. In this study, Mannosylated Chitosan Nanoparticles (MCN) loaded with FliC protein were synthesized as a targeted vaccine delivery system. The immunogenicity and protective efficacy of FliC and FliC-MCN against Brucella infection were evaluated in BALB/c mice. After cloning, expression and purification, FliC protein was loaded on MCN. The particle size, loading efficiency and in vitro release of the NPs were determined. Our investigation revealed that FliC and FliC-MCN could significantly increase specific IgG response (higher IgG2a titers). Besides, spleen cells from immunized mice produced high level of IFN-γ and IL-2 and low level IL-10 cytokines. Immunization with FliC and FliC-MCN conferred significant degree of protection against B. melitensis 16 M and B. abortus 544 infections. Overall these results indicate that FliC protein would be a novel potential antigen candidate for the development of a subunit vaccine against B. melitensis and B. abortus. Moreover, MCN could be used as an adjuvant and targeted vaccine delivery system., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

The mucosal immune system serves as the first line of defense against Bordetella pertussis . Intranasal vaccination, due to its potential to induce systemic and mucosal immune responses, appears to prevent the initial adherence and colonization of the bacteria at the first point of contact. In the present study, two B. pertussis antigens, pertussis Toxoid (PTd) and Filamentous hemagglutinin (FHA), which play a very significant role in virulence and protection against pertussis, were encapsulate into N-trimethyl chitosan (TMC) nanoparticulate systems. After preparation of TMC nanoparticles (NPs), the NPs were characterized and their ability to induce efficient immune responses against B. pertussis was studied in a mouse model. Our findings showed that PTd + FHA-loaded TMC NPs have strong ability to induce IL-4, IL-17, IFN-γ, IgG, and IgA in the mouse model. Results from this study suggest that nasal administration of the PTd + FHA-loaded TMC NPs induced not only a systemic immune response but also a local mucosal response, which may improve the efficacy of pertussis prevention through respiratory tract transmission.

Brucella (B) species are brucellosis causative agents, a worldwide zoonotic illness causing Malta fever in humans and abortion in domestic animals. In this work, we evaluated the vaccine potential of Trimethyl chitosan (TMC) nanoparticles formulation of Urease (TMC/Urease) against brucellosis. TMC/Urease nanoparticles and urease without any adjuvant were separately administered both orally and intraperitoneally. Intraperitoneal (i.p.) administration of urease alone as well as oral administration of both TMC/Urease nanoparticles and urease alone, elicited low titers of specific immunoglobulin G (IgG), while i.p. immunization with TMC/Urease nanoparticles induced high specific IgG production levels. As it was indicated by the cytokine assay and the antibody isotypes, i.p. immunization by urease alone, and TMC/Urease nanoparticles induced a mixed Th1-Th2 immune response, whereas oral administration of both urease alone and TMC/Urease nanoparticles induced a mixed Th1-Th17 immune response. In lymphocyte proliferation assay, spleen cells from i.p.-vaccinated mice with TMC/Urease nanoparticles showed a strong recall proliferative response. Vaccinated animals were challenged with virulent strains of B. melitensis and B. abortus. I.p. vaccination with TMC/Urease nanoparticles resulted in a high degree of protection. Altogether, our results indicated that TMC nanoparticles are a potent delivery system for i.p.-administered Brucella antigens., (Copyright © 2018. Published by Elsevier B.V.)

The lipopolysaccharide (LPS) of Vibrio cholerae (V. cholerae) plays an important role in cholera disease and the induction of primary protection. In this study, we evaluate mice humoral immune response in intranasal and intraperitoneal administrated V. cholerae LPS. The results showed that the intranasal administration of LPS-chitosan nanoparticle induced the high level of antibodies compared to intraperitoneal injection of antigen without chitosan (P < .001). These results indicated that intranasal and intraperitoneal administration of LPS has been able to induce the high level of antibodies both in the sera and lavage fluid and confirmed our strategy for using intranasal administration of antigen.

Brucellosis is a group of closely associated zoonotic bacterial illnesses caused by members of the genus Brucella. B. melitensis Omp31 is a promising candidate for a subunit vaccine against brucellosis. This study surveyed the immunogenicity of Omp31 alone and with incomplete Freund's adjuvant (Omp31-IFA) and N -trimethyl chitosan (TMC/Omp31) nanoparticles (NPs), as well as the effect of Omp31 immunization route on immunological responses and protection. After expression and purification, the recombinant Omp31 (rOmp31) was loaded onto TMC NPs by ionic gelation. The particle size, loading efficiency and in vitro release of the NPs were examined. Omp31-IFA was administered intraperitoneally, while TMC/Omp31 NPs were administered orally and intraperitoneally. According to the antibody subclasses and cytokine profile, intraperitoneal immunization by Omp31-IFA and TMC/Omp31 NPs induced T helper 1 (Th1) and Th1-Th2 immune responses, respectively. On the other hand, oral immunization with TMC/Omp31 NPs elicited a mixed Th1-Th17 immune response. Data obtained from the cell proliferation assay showed that vaccination with Omp31 stimulated a vigorous antigen-specific cell proliferative response, which could be further increased after oral immunization with TMC/Omp31 NPs. Vaccinated groups of mice when challenged with B. melitensis 16M were found to be significantly protected in the orally administered group in comparison with the intraperitoneally immunized mice. Results of this study indicated that the reason for high protection after oral vaccination can be via elicited Th17 response., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Many materials such as aluminum hydroxide have been tried as adjuvants to compensate low inherent immunogenicity of subunit vaccines. The aim of this study was to evaluate the specific immune response following the administration of aluminum hydroxide nanoparticles with EsxV antigen. The physiochemical properties of the nanoparticle were characterized in vitro. After subcutaneous immunization, cytokine secretion patterns including IFN-gama,IL-4, and TGF-beta levels were measured by indirect enzyme linked immunosorbent assay (ELISA). Aluminum hydroxide-NPs were demonstrated excellent effects to raise of IFN-γ secretion in compare to EsxV alone. Administration of aluminum hydroxide nanoparticles stimulates strong cellular immune response and could be considered as appropriate adjuvant against TB infection.

Background & Objective: Nanomedicine delivery systems are known as potent therapeutictools. In addition to possessing an effective agent of turmeric, Curcumin shows antibacterial properties as well. Curcumin is not water-soluble and it can be solved in water via nanotechnology-base methods. Chitosan is a natural and biodegradable substance that is utilized for the Production of Nanoparticles (NPs) carrying drug. In the following investigation, curcumin is loaded in chitosan NPs and ultimately, the resulting nano-drug is studied as an antibacterial agent. Materials & Methods: In this study, NPs are produced using chitosan and Tripolyphosphate (TPP) salt. Curcumin solution was loaded in chitosan NPs during their production. Next, the skins of BALB/c mice infected with staphylococcus aureus are treated by curcumin-loaded chitosan NPs for 3 days. Afterwards, in order to evaluate the antibacterial property of the nano-drug, these skin suspensions of mice are cultured in bacterial medium. Results: Dynamic Light Scattering (DLS) reveals the charge of + 7 ± 2 mV and the size of 160 ± 10 nm in curcuminloaded chitosan NPs. Moreover, Transmission electron microscopy (TEM) and atomic force microscopy (AFM) indicates a spiral shape. Therefore, the evaluation of the optical density by spectrophotometry demonstrates that 75 ± 2 % of curcumin are loaded in chitosan NPs. Bacterial culture shows that curcumin-loaded chitosan NPs significantly inhibited staphylococcus aureus growth. Conclusion: This study demonstrates that curcumin-loaded chitosan NPs can be applied as a potent agent in treatment of bacterial skin infections. [ABSTRACT FROM AUTHOR]