Enhancement of host infectivity, immunity, and protective efficacy by addition of sodium bicarbonate antacid to oral vaccine formulation of live attenuated Salmonella secreting Brucella antigens

Physiological role of bicarbonate in microbes: A double-edged sword?

HCO3- is involved in pH homoeostasis and plays a multifaceted role in human health. HCO3- has been recognized for its antimicrobial properties and is pivotal in bacterial antibiotic susceptibility. Notably, the interconversion between CO2 and HCO3-, facilitated by the enzyme carbonic anhydrase (CA), is crucial in tissues infected by pathogens. Studies have highlighted the antimicrobial potency of CA inhibitors, emphasizing the importance of this enzyme in this area. The potential of HCO3- as an antibiotic adjuvant is evident; its ability to increase virulence in pathogens such as Enterococcus faecalis and Mycobacterium tuberculosis requires meticulous scrutiny. HCO3- modulates bacterial behaviours in diverse manners: it promotes Escherichia coli O157:H7 colonization in the human gut by altering specific gene expression and, with Pseudomonas aeruginosa, amplifies the effect of tobramycin on planktonic cells while promoting biofilm formation. These multifaceted effects necessitate profound mechanistic exploration before HCO3- can be considered a promising clinical adjuvant.

Vitamins as excipients in pharmaceutical products

Excipients are ingredients in pharmaceutical products other than the active ingredient, added to facilitate manufacturing, enhance stability or modulate release and bioavailability. Vitamins are diverse molecules essential for human nutrition that also can fulfil excipient functions. This review focuses on vitamins used as excipients and provides an overview of the functions of vitamins in various pharmaceutical formulations. A thorough search was conducted to understand the current use of vitamins in marketed drug products, concluding that many vitamins are already used as functional excipients. Vitamins are used widely in different dosage forms, including oral, parenteral, and topical formulations, and alongside a broad range of active pharmaceutical ingredients, biologics, and small molecules from different biopharmaceutical classification system classes. Many examples of the use of vitamins to improve the performance of the pharmaceutical formulation in which they are included are presented and the mode of action of vitamins as excipients in the product is reviewed. Furthermore, the potential for future uses of vitamins in pharmaceutical products is highlighted. Lastly, considerations for the use of vitamins as excipients in drug products as well as the regulatory framework are discussed.

Recent Advances in Oral Vaccines for Animals

Compared to traditional injected vaccines, oral vaccines offer significant advantages for the immunization of livestock and wildlife due to their ease of use, high compliance, improved safety, and potential to stimulate mucosal immune responses and induce systemic immunity against pathogens. This review provides an overview of the delivery methods for oral vaccines, and the factors that influence their immunogenicity. We also highlight the global progress and achievements in the development and use of oral vaccines for animals, shedding light on potential future applications in this field.

Evasion of host defense by Brucella

Brucella , an adept intracellular pathogen, causes brucellosis, a zoonotic disease leading to significant global impacts on animal welfare and the economy. Regrettably, there is currently no approved and effective vaccine for human use. The ability of Brucella to evade host defenses is essential for establishing chronic infection and ensuring stable intracellular growth. Brucella employs various mechanisms to evade and undermine the innate and adaptive immune responses of the host through modulating the activation of pattern recognition receptors (PRRs), inflammatory responses, or the activation of immune cells like dendritic cells (DCs) to inhibit antigen presentation. Moreover, it regulates multiple cellular processes such as apoptosis, pyroptosis, and autophagy to establish persistent infection within host cells. This review summarizes the recently discovered mechanisms employed by Brucella to subvert host immune responses and research progress on vaccines, with the aim of advancing our understanding of brucellosis and facilitating the development of more effective vaccines and therapeutic approaches against Brucella .

Assessment of environmental safety and protective efficacy of O-antigen deficient DIVA capable Salmonella Enteritidis against chicken salmonellosis

In this study, we incorporated deletion of the O-antigen ligase gene to an attenuated Salmonella Enteritidis (SE) strain, JOL919 (SE PS; Δlon ΔcpxR), using the Lambda-Red recombination method and evaluated the safety and immunological aspects of the novel genotype, JOL2381 (SE VS: Δlon, ΔcpxR, ΔrfaL). Assessment of fecal shedding and organ persistence following administration via oral and IM routes revealed that the SE VS was safer than its parent strain, SE PS. Immunological assays confirmed that immunization via the oral route with SE PS was superior to the SE VS. However, chickens immunized with SE PS and SE VS strains via the IM route showed higher humoral and cell-mediated immune responses. Compared to PBS control, the IM route of immunization with SE VS resulted in a higher IgY antibody titer and expansion of CD4+ and CD8+ T-cell populations, which resulted in the clearance of Salmonella from the liver and splenic tissues. Furthermore, deletion of the O-antigen ligase gene caused lower production of LPS-specific antibodies in the host, promoting DIVA functionality and making it a plausible candidate for field utilization. Due to significant protection, high attenuation, and environmental safety concerns, the present SE VS strain is an ideal choice to prevent chicken salmonellosis and ensure public health.

Safety assessment of compliant, highly invasive, lipid A-altered, O-antigen-defected Salmonella strains as prospective vaccine delivery systems

In the present study, two prospective Salmonella delivery strains, JOL2782 and JOL2837, were developed by gene deletions of lon and cpxR, which are related to cellular adhesion and intracellular survival. Additionally, sifA deletion was introduced for JOL2782, which confers immune susceptibility and improves antigen delivery. Similarly, the rfaL deletion and lpxE substitution for pagL were accomplished in JOL2837 to reduce virulence and endotoxicity. Thus, enhanced adhesion and invasion and reduced intracellular survival were attained. Furthermore, aspartic acid auxotrophic (asd) was deleted to impose Darwinian selection on retention of the foreign antigen-expressing plasmid. Both delivery strains induced sufficient cytokine expression, but the level was significantly lower than that of the wild-type strain; the lowest cytokine expression was induced by the JOL2837 strain, indicating reduced endotoxicity. In parallel, IgG production was significantly enhanced by both delivery strains. Thus, the innate and adaptive immunogenicity of the strains was ensured. The environmental safety of these strains was ascertained through faecal dissemination assays. The nonpathogenicity of these strains to the host was confirmed by body weight monitoring, survival assays, and morphological and histological assessments of the vital organs. The in vitro assay in murine and human cell lines and in vivo safety assessments in mice suggest that these novel strains possess safety, invasiveness, and immunogenicity, making them ideal delivery strains. Overall, the results clearly showed that strain JOL2782 with sifA deletion had higher invasiveness, demonstrating superior vaccine deliverability, while JOL2837 with lpxE substitution for pagL and rfaL deletion had outstanding safety potential with drastically abridged endotoxicity.

Evaluation of Brucellosis Vaccines: A Comprehensive Review

Brucellosis is a bacterial zoonosis caused by Brucella spp. which can lead to heavy economic losses and severe human diseases. Thus, controlling brucellosis is very important. Due to humans easily gaining brucellosis from animals, animal brucellosis control programs can help the eradication of human brucellosis. There are two popular vaccines against animal brucellosis. Live attenuated Brucella abortus strain 19 (S19 vaccine) is the first effective and most extensively used vaccine for the prevention of brucellosis in cattle. Live attenuated Brucella melitensis strain Rev.1 (Rev.1 vaccine) is the most effective vaccine against caprine and ovine brucellosis. Although these two vaccines provide good immunity for animals against brucellosis, the expense of persistent serological responses is one of the main problems of both vaccines. The advantages and limitations of Brucella vaccines, especially new vaccine candidates, have been less studied. In addition, there is an urgent need for new strategies to control and eradicate this disease. Therefore, this narrative review aims to present an updated overview of the available different types of brucellosis vaccines.

Quality by Design Applied Development of Immediate-Release Rabeprazole Sodium Dry-Coated Tablet

The aim of this study was to develop immediate-release oral rabeprazole sodium tablets with rapid efficacy and gastric stability for the treatment of gastroesophageal reflux disease. Rabeprazole sodium is a commonly prescribed proton pump inhibitor; however, it is extremely unstable and degrades in acidic environments. Hence, it has been manufactured and supplied only in enteric-coated tablet form, while immediate-release (IR) formulations for this drug are very limited. In this study, we applied the quality by design (QbD) approach to formulate and optimize an IR dry-coated tablet containing rabeprazole sodium as an inner core with an outer sodium bicarbonate layer to stabilize the active pharmaceutical ingredient at gastric pH. We also investigated the stability of the pharmaceutical dosage form and its pharmacokinetic profile. The results show that the developed tablets are stable for approximately 12 months and have a high dissolution rate, greater than or equal to 90% at 30 min. Further, in vivo beagle pharmacokinetics confirmed that the newly developed IR tablet had an AUC_t which is bioequivalent to the existing delayed-release rabeprazole tablet; however, its T_max was 0.5 h, which is up to seven times faster than that of the existing tablet. Moreover, the IR tablet was found to immediately absorb in the stomach. Hence, the development of IR tablets can be used as a platform to overcome the technical and commercial limitations currently associated with various proton pump inhibitors used to treat patients with gastroesophageal reflux disease that require immediate therapeutic relief.

O-antigen-deficient, live, attenuated Salmonella typhimurium confers efficient uptake, reduced cytotoxicity, and rapid clearance in chicken macrophages and lymphoid organs and induces significantly high protective immune responses that protect chickens against Salmonella infection

In the present study, we developed an O-antigen-deficient, live, attenuated Salmonella Typhimurium (ST) strain (JOL2377) and assessed its safety, macrophage toxicity, invasion into lymphoid tissues, immunogenicity, and protection against Salmonella infection in chickens. The JOL2377 induced significantly lower cytotoxicity and higher level of cytokine response in IL-2, IL-10, IL-4, and IFN- γ than the WT strain upon macrophage uptake. It did not persist in macrophages or in chicken organs and rapidly cleared without systemic infection. None of the chicken were found to secrete Salmonella in feces into the environment exacerbating its attenuation. Interestingly JOL2377 successfully arrived in immunological hot-spots such as spleen, liver and bursa of Fabricius for an efficient antigen presentation and immune stimulation. Mucosal and parenteral immunization with JOL2377 significantly elicit antigen-specific humoral (IgY) and cell mediated responses marked by peripheral blood mononuclear cell proliferation, cytokine induction, increase in T-cell responses than non-immunized control. JOL2377 did not generate significant levels of LPS specific antibodies as compared to the WT strain due to the lack of immunogenic O-antigen component from its LPS structure. Upon virulent challenge, route dependent efficacy differences were leaving the intramuscular route is superior to the oral route on reducing splenic and liver colonization of the challenge ST. The least cytotoxicity, virulence, and superior immunogenicity of JL2377 that effectively engage both humoral and IFN- γ mediated CMI responses present an ideal scenario in host immune modulation to fight against intracellular pathogen Salmonella.