An approach to chimeric subunit immunogen provides efficient protection against toxicity, type III and type v secretion systems of Shigella

HeterologousPrime-Boost immunizationwithAdenoviral vector and recombinant subunit vaccines strategies against dengue virus type2

Dengue virus (DENV) remains a significant public health threat in tropical and subtropical regions, with effective antiviral treatments and vaccines still not fully established despite extensive research. A critical aspect of vaccine development for DENV involves selecting proteins from both structural and non-structural regions of the virus to activate humoral and cellular immune responses effectively. In this study, we developed a novel vaccine for dengue virus serotype 2 (DENV2) using a heterologous Prime-Boost strategy that combines an adenoviral vector (Ad) with subunit vaccines. The vaccine design included non-structural protein 1 (NS1), envelope protein domain III (EDIII), and the bc-loop of envelope domain II (EDII) as conserved epitopes. These antigens were fused into a single construct P1 and inserted into the pAdTrack-CMV vector to produce a recombinant adenovirus (rAd5-P1) via homologous recombination in E. coli. The examination of the immune response indicated that strong humoral and cellular immunity was generated in various groups of mice. Additionally, the group receiving a heterologous regimen of recombinant adenovirus and protein showed a superior balance of humoral and cellular immunity in terms of IgG2a/IgG1 and INF-γ /IL-4 ratios. These findings validate the vaccine design's ability to utilize both structural and non-structural proteins to generate strong immune responses on two platforms. The promising results from the heterologous regimen highlight its potential as an effective DENV2 vaccine candidate. This research offers significant insights into developing safe and effective DEN vaccines, contributing to efforts to control DENV infections.

A broad spectrum Shigella vaccine based on VirG53-353 multiepitope region produced in a cell-free system

Dysentery caused by Shigella species remains a major health threat to children in low- and middle-income countries. There is no vaccine available. The most advanced candidates, i.e., O-polysaccharide (OPS)-based conjugates, have limited coverage-only against the immunizing serotype. Vaccines based on Shigella conserved proteins are sought for their simplicity and capacity to prevent disease caused by multiple serotypes. We previously reported the broad protective capacity of VirGα, a conserved surface-exposed domain of Shigella virulence factor. Seeking to refine the vaccine antigenic target and achieve scalable manufacturing compatible with Good Manufacturing Practices, we mapped linear B-cell epitopes spanning the entire VirG protein sequence by probing the immune reactivity of 10-mer peptides (overlapping 4-8 aa) with sera from Shigella-infected rhesus monkeys. The surface-exposed VirG53-353 subregion of the passenger α-domain demonstrated the highest and strongest immunoreactivity. VirG53-353 was produced efficiently at a large scale (>150 mg/L) using cell-free protein synthesis. When administered to mice intramuscularly, VirG53-353 elicited robust antibody responses and conferred high levels of protection against the three most prevalent Shigella serotypes (S. flexneri 2a, 3a, and S. sonnei). VirG53-353 evoked the production of Th2-type cytokines by spleen cells from vaccinated mice. A new universal Shigella vaccine based on VirG53-353 meets the World Health Organization's preferred product specifications. The target antigen refinement and production improvement described here will facilitate the first-in-human studies.

Therapeutic efficacy of SipD/LptD-specific IgY entrapped in alginate nanoparticles against Salmonella Typhimurium infection

Introduction

Salmonella, a zoonotic pathogen causing gastroenteritis, lacks a preventive vaccine. Passive immunization with IgY antibodies derived from immunized chickens has shown potential for treating bacterial infections. This study investigated the therapeutic efficacy of entrapped IgY targeting recombinant SipD and LptD proteins from Salmonella Typhimurium.

Methods

The recombinant protein was expressed in E. coli BL21 (DE3) and purified using Ni-NTA affinity chromatography. Hens were immunized with the purified protein, and the resulting IgY was entrapped into alginate nanoparticles. The shape of spherical nanoparticles and their size in the nanometer range were determined by SEM and DLS analysis. The therapeutic efficacy of free and alginate-entrapped IgY against S. Typhimurium was evaluated in mice at 1, 50, and 100 LD50 bacterial doses.

Results

The purified IgY concentration in each egg yolk was 6 mg/ml (35 mg/egg). Physicochemical and structural characterization revealed spherical nanoparticles with a diameter of 157.1 nm and a negatively charged surface (zeta potential of -35.6 mV). The loading efficiency of IgY into alginate nanoparticles was 95.5 %. In a challenge test with 100 LD50 of S. Typhimurium, all mice receiving alginate-entrapped IgY survived, whereas half of the mice receiving non-entrapped IgY died within 7 days.

Conclusion

Our results indicate that IgY antibodies entrapped in alginate nanoparticles may offer therapeutic effect against S. Typhimurium infection.

Artificial intelligence in healthcare: a mastery

There is a vast development of artificial intelligence (AI) in recent years. Computational technology, digitized data collection and enormous advancement in this field have allowed AI applications to penetrate the core human area of specialization. In this review article, we describe current progress achieved in the AI field highlighting constraints on smooth development in the field of medical AI sector, with discussion of its implementation in healthcare from a commercial, regulatory and sociological standpoint. Utilizing sizable multidimensional biological datasets that contain individual heterogeneity in genomes, functionality and milieu, precision medicine strives to create and optimize approaches for diagnosis, treatment methods and assessment. With the arise of complexity and expansion of data in the health-care industry, AI can be applied more frequently. The main application categories include indications for diagnosis and therapy, patient involvement and commitment and administrative tasks. There has recently been a sharp rise in interest in medical AI applications due to developments in AI software and technology, particularly in deep learning algorithms and in artificial neural network (ANN). In this overview, we enlisted the major categories of issues that AI systems are ideally equipped to resolve followed by clinical diagnostic tasks. It also includes a discussion of the future potential of AI, particularly for risk prediction in complex diseases, and the difficulties, constraints and biases that must be meticulously addressed for the effective delivery of AI in the health-care sector.

Evaluation of the prophylactic effect of egg yolk antibody (IgY) produced against the recombinant protein containing IpaD, IpaB, StxB, and VirG proteins from Shigella

INTRODUCTION

Shigellosis is a gastrointestinal disease causes high morbidity and mortality worldwide, however, there is no anti-Shigella vaccine. The use of antibiotics in shigellosis treatment exacerbates antibiotic resistance. Antibodies, particularly egg yolk antibody (IgY), offer a promising approach to address this challenge. This study aimed to investigate the prophylactic effect of IgY produced against a recombinant chimeric protein containing the immunogens IpaD, IpaB, StxB, and VirG from Shigella.

METHODS

The chimeric protein, comprising IpaD, IpaB, StxB, and VirG, was expressed in E. coli BL21 and purified using the Ni-NTA column. Following immunization of chickens, IgY was extracted from egg yolk using the PEG-6000 method and analyzed through SDS-PAGE and ELISA techniques. Subsequently, the prophylactic efficacy of IgY was assessed by challenging of mice with 10 LD50 of S. dysenteriae and administering different concentrations of IgY (1.25, 2.5, 5, and 10 mg/kg) under various time conditions.

RESULTS

The recombinant protein, weighing 82 kDa, was purified and confirmed by western blotting. The IgY concentration was determined as 9.5 mg/ml of egg yolk and the purity of the extracted IgY was over 90 %. The results of the ELISA showed that at least 19 ng of pure antibody identified recombinant protein and reacts with it. The challenge test employing IgY and Shigella demonstrated a direct correlation between the survival rate and antibody concentration, with increased concentrations leading to decreased mortality rates. Treatment of mice with 10 mg/kg IgY leads to 80 % survival of the mice against 10 LD50 S. dysenteriae.

CONCLUSION

Our findings suggest that IgY may offer therapeutic potential in treating Shigella infections and combating antibiotic resistance.

Shigella Vaccines: The Continuing Unmet Challenge

Shigellosis is a severe gastrointestinal disease that annually affects approximately 270 million individuals globally. It has particularly high morbidity and mortality in low-income regions; however, it is not confined to these regions and occurs in high-income nations when conditions allow. The ill effects of shigellosis are at their highest in children ages 2 to 5, with survivors often exhibiting impaired growth due to infection-induced malnutrition. The escalating threat of antibiotic resistance further amplifies shigellosis as a serious public health concern. This review explores Shigella pathology, with a primary focus on the status of Shigella vaccine candidates. These candidates include killed whole-cells, live attenuated organisms, LPS-based, and subunit vaccines. The strengths and weaknesses of each vaccination strategy are considered. The discussion includes potential Shigella immunogens, such as LPS, conserved T3SS proteins, outer membrane proteins, diverse animal models used in Shigella vaccine research, and innovative vaccine development approaches. Additionally, this review addresses ongoing challenges that necessitate action toward advancing effective Shigella prevention and control measures.

Production of egg yolk antibody (IgY) against a chimeric protein containing IpaD, StxB, and TolC antigens from Shigella: An investigation of its prophylactic effects against Shiga toxin (Stx) and Shigella dysenteriae in vitro and in vivo

Shigella is a major problem in developing countries. Immunoglobulin Y (IgY) can be used for prophylaxis and neutralize bacteria. The aim of this study was to produce IgY against the chimeric protein containing IpaD, StxB, and TolC antigens from Shigella, investigate its prophylactic and neutralizing effects against Stx and Shigella dysenteriae. The nucleotide sequence corresponding to the chimeric protein was cloned into pET28a plasmid and expressed in E. coli BL21 (DE3). Protein expression was confirmed by SDS-PAGE and the recombinant protein was purified by Ni-NTA affinity chromatography. The 150 μg of chimeric protein was mixed with Freund's adjutant and injected into laying hens (Leghorn). IgY was purified using PEG6000 precipitation. Antibody titer in the serum and egg yolk was evaluated by ELISA. IgY challenge against 1,10 and 50 LD50 of Stx and S. dysenteriae was investigated. A 60.6 kDa recombinant protein was confirmed by SDS-PAGE. ELISA showed that the antibody titer was significantly increased. MTT assay [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] showed that at 16 μmol/L, IgY protected HeLa cells against Stx. Treatment of mice with 1000 and 1500 μg IgY leads to complete survival of the mice against 1LD50 toxin and 4000 μg of IgY led to complete survival against 1LD50, also 70% and 30% survival against 10 and 50 LD50S. dysenteriae. This study showed that IgY produced against Stx and Shigella virulence factors could cause high protective effects against bacteria and toxins.

Investigate the immunogenic and protective effect of trivalent chimeric protein containing IpaD-StxB-TolC antigens as a vaccine candidate against S. dysenteri and S. flexneri

BACKGROUND

s: Shigella spp. causes bloody diarrhea and leads to death, especially in children. Chimeric proteins containing virulence factors can prevent Shigella infection. The purpose of this study is to investigate the immunogenic and protective effect of trivalent chimeric protein containing IpaD-StxB-TolC antigens against shiga toxin, S. dysenteri and S. flexneri in vitro and in vivo conditions.

METHODS

Recombinant vector was transferred to E. coli BL21. The expression of the chimeric protein was confirmed by SDS PAGE and purified using the Ni-NTA column. Mice were immunized with recombinant protein and antibody titer was evaluated by ELISA. 10, 25 and 50 LD₅₀ of Shiga toxin neutralization was evaluated in vitro (Vero cell line) and in vivo conditions. Also, the challenge of immunized mice with 10, 25 and 50 LD₅₀ of S. dysentery and S. flexneri was done.

RESULTS

The expression and purification of the recombinant protein with 60.6 kDa was done. ELISA showed increased antibody titer against the chimeric protein. MTT assay indicated that 1/8000 dilution of the sera had a 51% of cell viability against the toxin in Vero cell line. The challenge of mice immunized with toxin showed that the mice had complete protection against 10 and 25 LD₅₀ of toxin and had 40% survival against 50 LD₅₀. Mice receiving 10 and 25 LD₅₀ of S. dysenteri and S. flexneri had 100% protection and in 50 LD₅₀ the survival rate was 60 and 50%, respectively. Organ burden showed that the amount of bacterial colonization in immunized mice was 1 × 10⁴ CFU/mL, which was significantly different from the control group.

CONCLUSION

This study showed that chimeric proteins can create favorable immunogenicity in the host as vaccine candidates.