Administration Of Oral Vaccine Research Articles

Barley as a production platform for oral vaccines in sustainable fish aquaculture

Vaccination is the most effective measure to prevent disease outbreaks in fish aquaculture, with oral vaccine administration emerging as the most practical approach. However, oral vaccines face a notable limitation due to insufficient stimulation of the complex gut-associated lymphoid tissue caused by factors such as vaccine degradation, poor absorption, and recognition by the immune cells. An innovative solution to these limitations lies in the plant-based production of recombinant vaccines. Plant cells enable the production and targeted storage of recombinant vaccines in specific cell organelles which ensure superior protection from degradation and contain natural compounds acting as adjuvants. Our study explores the potential of barley (Hordeum vulgare), a globally significant cereal crop, for producing orally administered subunit vaccines against viral infections affecting economically important fish species in the Salmonidae and Cyprinidae families. Through Agrobacterium-mediated transformation of immature barley embryos, we have generated homozygous T2 generation of transgenic barley expressing recombinant antigens of spring viremia of carp virus and infectious salmon anaemia virus. The expression of these plant-based recombinant vaccines was confirmed by immunodetection, which was supported by fluorescence observation, specifically in the seed endosperm. The antigenicity of transgenic plant material containing recombinant antigens was evaluated using an intubation model of common carp (Cyprinus carpio), revealing a substantial upregulation of the immunoglobulin transcripts in both systemic and mucosal tissues over a period of 28 days following a single dose of transgenic antigens. Collectively, these results underscore the potential of barley-based recombinant vaccines for disease prevention in fish aquaculture.

Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice.

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

Polymeric Nanoparticles as Oral and Intranasal Peptide Vaccine Delivery Systems: The Role of Shape and Conjugation.

Mucosal vaccines are highly attractive due to high patient compliance and their suitability for mass immunizations. However, all currently licensed mucosal vaccines are composed of attenuated/inactive whole microbes, which are associated with a variety of safety concerns. In contrast, modern subunit vaccines use minimal pathogenic components (antigens) that are safe but typically poorly immunogenic when delivered via mucosal administration. In this study, we demonstrated the utility of various functional polymer-based nanostructures as vaccine carriers. A Group A Streptococcus (GAS)-derived peptide antigen (PJ8) was selected in light of the recent global spread of invasive GAS infection. The vaccine candidates were prepared by either conjugation or physical mixing of PJ8 with rod-, sphere-, worm-, and tadpole-shaped polymeric nanoparticles. The roles of nanoparticle shape and antigen conjugation in vaccine immunogenicity were demonstrated through the comparison of three distinct immunization pathways (subcutaneous, intranasal, and oral). No additional adjuvant or carrier was required to induce bactericidal immune responses even upon oral vaccine administration.

Acid resilience oral mucosal delivery for vaccination against Hepatitis-B

The predominant mode of transmission for the viral infection that causes hepatitis B as the major reason of liver cirrhosis and hepatocellular carcinoma is by the parenteral or permucosal route. M-cell targeted acid-resistant oral vaccine administration has been developed for Hepatitis B infection prevention. The solvent injection approach was used to create cationic solid lipid nanoparticles (cSLNs). Alginate-coated cSLNs loaded with hepatitis B surface antigen (HBsAg) were conjugated with lipopolysaccharide (LPS). To assess the produced formulation's resistance against acid degradation, SDS-PAGE was used. ELISA assays were used to measure anti-HBsAgIgG/IgA antibodies in mucosal fluids after female Balb/c mice were used to determine the induction of immunity induced by manufactured nanoparticle for hepatitis B infection prevention. After 48 h, alginate-coated cSLNs showed sustained releasing of HBsAg compared to cSLNs devoid of alginate coating. Anti-HBsAG was produced in the intestinal, salivary, and vaginal secretions at levels that were comparatively elevated in comparison to that of the control group, which had an anti-HBsAG titer of 0.25 IU/ml. After binding with SLN, the M-cells' integrity was preserved, and the oral administration helped the antigen reach the gut where it was most needed. It was discovered to be successful at generating antibodies during the mucosal immunization against the hepatitis B virus. As a result, LPS-conjugated alginate-coated cSLNs loaded with HBsAg offers a promising substitute for an existing vaccine for the prevention of hepatitis B infection.

Effects of two delivery matrix components, alginate and polyethylene glycol, on the intestinal tract and inflammatory response of juvenile rainbow trout, Oncorhynchus mykiss, Walbaum

AbstractA critical step in the administration of oral vaccines in aquaculture is the effective protection of the vaccine antigens through the delivery route of water to stomach to the mucosal immune system in the gut. Bioactive substances can be incorporated into protective matrices to ensure safe ingestion and controlled release into the posterior digestive tract. Polyethylene glycol and alginate are promising and frequently applied substances in the oral administration of pharmaceutical substances; however, their direct influence on the intestinal tract or inflammatory response is not well investigated in aquaculture fish. In the current study, these two substances were evaluated separately and in combination. They were included in a commercial diet for juvenile rainbow trout (18.7 ± 0.1 g) and applied over 22 days in controlled feeding to determine possible gut alterations and inflammatory responses. Three different sections of the intestine, the anterior pyloric caeca, the mid‐intestine, and the posterior intestine, were histologically examined, and expression of inflammatory genes was measured in each. The inclusion of polyethylene glycol in the diet led to a significant reduction of villus height in the pyloric caeca and thus a significant reduction in active surface area. In the mid‐intestine, alginate inclusion resulted in a significant reduction of the mucus‐secreting goblet cells and a significant increase in villus width. In the posterior intestine, polyethylene glycol inclusion caused a significant increase in number of large vacuoles present; the addition of alginate buffered this effect. The results of the histological evaluation indicated symptoms that are usually evident in intestinal inflammation and can reduce functions of the respective intestinal segments. No significant increases in pro‐inflammatory gene expression tumor necrosis factor‐α, interleukin (IL)‐8, or IL‐1β were present, indicating no severe inflammatory response. Based on the observed histological impairments, negative consequences such as reduced efficiency of an oral vaccine or productivity of aquaculture rearing due to hindered nutrient digestion can be considered unlikely.

Yeast oral vaccines against infectious diseases.

Vaccines that are delivered orally have several advantages over their counterparts that are administered via injection. Despite the advantages of oral delivery, however, approved oral vaccines are currently limited either to diseases that affect the gastrointestinal tract or to pathogens that have a crucial life cycle stage in the gut. Moreover, all of the approved oral vaccines for these diseases involve live-attenuated or inactivated pathogens. This mini-review summarizes the potential and challenges of yeast oral vaccine delivery systems for animal and human infectious diseases. These delivery systems utilize whole yeast recombinant cells that are consumed orally to transport candidate antigens to the immune system of the gut. This review begins with a discussion of the challenges associated with oral administration of vaccines and the distinct benefits offered by whole yeast delivery systems over other delivery systems. It then surveys the emerging yeast oral vaccines that have been developed over the past decade to combat animal and human diseases. In recent years, several candidate vaccines have emerged that can elicit the necessary immune response to provide significant protection against challenge by pathogen. They serve as proof of principle to show that yeast oral vaccines hold much promise.

Recent Developments in Oral Delivery of Vaccines Using Nanocarriers.

As oral administration of vaccines is the preferred route due to its high patient compliance and ability to stimulate both cellular and humoral immune responses, it is also associated with several challenges that include denaturation of vaccine components in the acidic environment of the stomach, degradation from proteolytic enzymes, and poor absorption through the intestinal membrane. To achieve effective delivery of such biomolecules, there is a need to investigate novel strategies of formulation development that can overcome the barriers associated with conventional vaccine delivery systems. Nanoparticles are advanced drug delivery carriers that provide target-oriented delivery by encapsulating vaccine components within them, thus making them stable against unfavorable conditions. This review provides a detailed overview of the different types of nanocarriers and various approaches that can enhance oral vaccine delivery.

How modular protein nanoparticles may expand the ability of subunit anti-viral vaccines: The spring viremia carp virus (SVCV) case

Spring viremia of carp (SVC) remains as a vaccine orphan disease mostly affecting juvenile specimens. Young fish are especially difficult to vaccinate and oral administration of vaccine combined with food would be the election system to minimise stress and the vaccination costs associated to injection. However, administration of prophylactics with food pellets faces off several drawbacks mainly related with vaccine degradation and weak protection correlates of oral vaccines. Here we present a platform based on recombinant proteins (subunit vaccines) manufactured as highly resistant nanostructured materials, and providing excellent levels of protection against SVC virus in a preliminary i.p injection challenge. The G3 domain of SVCV glycoprotein G was overexpressed in E. coli together with IFNγ and the modular protein was purified from bacterial aggregates (inclusion bodies) as highly organised nanostructured biomaterial (nanopellets, NP). These SVCV-IFNNP were taken up by zebrafish cells leading to the enhanced expression of different antiviral and IFN markers (e.g vig1, mx, lmp2 or ifngr1 among others) in zebrafish liver cells (ZFL). To monitor if SVCVNP and SVCV-IFNNP can be taken up by intestinal epithelia and can induce antiviral response we performed experiments with SVCVNP and SVCV-IFNNP in 3 days post fertilization (dpf) zebrafish larvae. Both, SVCVNP and SVCV-IFNNP were taken up and accumulated in the intestine without signs of toxicity. The antiviral response in larvae showed a different induction pattern: SVCV-IFNNP did not induce an antiviral response while SVCVNP showed a good antiviral induction. Interestingly ZF4, an embryonic derived cell line, showed an antiviral response like ZFL cells, although the lmp2 and ifngr1 (markers of the IFNγ response) were not overexpressed. Experiments with adult zebrafish indicated an excellent level of protection against a SVCV model infection where SVCV-IFNNP vaccinated fish reached 20% cumulative mortality while control fish reached over 80% cumulative mortality.

Justification of tactical and technical sample requirements mass immunoprophylaxis dangerous infectious diseases in the Armed Forces of the Russian Federation

The results of the analysis of the current state of creating a technical means of mass immunoprophylaxis for dangerous infectious diseases are presented, including the technical level and trends in the development of developments on this problem in the Russian Federation and abroad. It was noted that in emergency situations of a biological nature, a vaccination campaign should be carried out in a short time with maximum personnel vaccination coverage, which is a massive undertaking. These requirements can be only be met with the use of mass vaccination in the form of needle-free, inhalation (aerosol) and oral vaccine administration methods. The wide use of these methods is constrained by a meager range of domestic oral vaccines, as well as the lack of technical means of mass immunization (aerosol generators, needleless injectors). This article shows that the needleless injector NI-30 (Russia) is the most appropriate for mass vaccination, in terms of technical level and operational characteristics. However, it cannot be recognized as fully meeting modern requirements due to a number of negative aspects, such as the rather large overall injector dimensions creating a large amount of obsolete structural materials. Thus, it is necessary to take into account the features of the available methods of vaccine administration when assessing the prospects for mass immunization, and it is necessary to substantiate the tactical and technical requirements for new generation samples in order to develop the technical means of mass immunization. Therefore, the development and introduction into practice of high-performance methods of mass immunization and the technical means for their implementation continues to be an urgent task.

Sublingual Vaccination with Live Influenza Virus Induces Better Protection Than Oral Immunization in Mice.

Both sublingual (SL) and oral vaccine administration modalities are convenient, easy, and safe. Here, we have investigated the differences in vaccine efficacy that are induced by oral and sublingual immunization with live influenza virus (A/Hong Kong/1/1968, H3N2) in mice. Intranasally administering a lethal dose of the influenza virus resulted in the deaths of the mice, whereas viral replication in the lungs did not occur upon SL or oral administration. At 30 days post-immunization through the SL or oral route, the mice were intranasally challenge-infected with the lethal dose of the homologous influenza virus. Both SL and oral immunizations with the influenza virus elicited significantly higher levels of virus-specific IgG and IgA antibody responses, as well as HAI titers in the sera. Upon challenge infection, the SL immunization elicited higher levels of pulmonary IgG antibody and CD8+ T cell responses than the oral immunization. Enhanced splenic germinal center B (GC B) and B cell proliferation were also detected from the SL immunization, both of which were significantly greater than those of the oral immunization. Importantly, compared to oral immunization, significantly lessened lung viral loads and bodyweight reductions were observed from the SL immunization and these parameters contributed to prolonging the survival of the immunized mice. These results indicate that both SL and oral administration could be effective routes in inducing protective immunity against influenza virus infection, with SL immunization being the better of the two delivery routes.

The evaluation of novel oral vaccines based on self-amplifying RNA lipid nanparticles (saRNA LNPs), saRNA transfected Lactobacillus plantarum LNPs, and saRNA transfected Lactobacillus plantarum to neutralize SARS-CoV-2 variants alpha and delta

The aim of this study was to present and evaluate novel oral vaccines, based on self-amplifying RNA lipid nanparticles (saRNA LNPs), saRNA transfected Lactobacillus plantarum LNPs, and saRNA transfected Lactobacillus plantarum, to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) variants alpha and delta. After invitro evaluation of the oral vaccines on HEK293T/17 cells, we found that saRNA LNPs, saRNA transfected Lactobacillus plantarum LNPs, and saRNA transfected Lactobacillus plantarum could express S-protein at both mRNA and protein levels. In the next step, BALB/c mice were orally vaccinated with saRNA LNPs, saRNA transfected Lactobacillus plantarum LNPs, and saRNA transfected Lactobacillus plantarum at weeks 1 and 3. Importantly, a high titer of IgG and IgA was observed by all of them, sharply in week 6 (P < 0.05). In all study groups, their ratio of IgG2a/IgG1 was upper 1, indicating Th1-biased responses. Wild-type viral neutralization assay showed that the secreted antibodies in vaccinated mice and recovered COVID-19 patients could neutralize SARS-COV-2 variants alpha and delta. After oral administration of oral vaccines, biodistribution assay was done. It was found that all of them had the same biodistribution pattern. The highest concentration of S-protein was seen in the small intestine, followed by the large intestine and liver.

Protection of Teleost Fish against Infectious Diseases through Oral Administration of Vaccines: Update 2021.

Immersion and intraperitoneal injection are the two most common methods used for the vaccination of fish. Because both methods require that fish are handled and thereby stressed, oral administration of vaccines as feed supplements is desirable. In addition, in terms of revaccination (boosting) of adult fish held in net pens, oral administration of vaccines is probably the only feasible method to obtain proper protection against diseases over long periods of time. Oral vaccination is considered a suitable method for mass immunization of large and stress-sensitive fish populations. Moreover, oral vaccines may preferably induce mucosal immunity, which is especially important to fish. Experimental oral vaccine formulations include both non-encapsulated and encapsulated antigens, viruses and bacteria. To develop an effective oral vaccine, the desired antigens must be protected against the harsh environments in the stomach and gut so they can remain intact when they reach the lower gut/intestine where they normally are absorbed and transported to immune cells. The most commonly used encapsulation method is the use of alginate microspheres that can effectively deliver vaccines to the intestine without degradation. Other encapsulation methods include chitosan encapsulation, poly D,L-lactide-co-glycolic acid and liposome encapsulation. Only a few commercial oral vaccines are available on the market, including those against infectious pancreatic necrosis virus (IPNV), Spring viremia carp virus (SVCV), infectious salmon anaemia virus (ISAV) and Piscirickettsia salmonis. This review highlights recent developments of oral vaccination in teleost fish.

Acidification induces condensation of the adenovirus core

The adenovirus (AdV) icosahedral capsid encloses a nucleoprotein core formed by the dsDNA genome bound to numerous copies of virus-encoded, positively charged proteins. For an efficient delivery of its genome, AdV must undergo a cascade of dismantling events from the plasma membrane to the nuclear pore. Throughout this uncoating process, the virion moves across potentially disruptive environments whose influence in particle stability is poorly understood. In this work we analyze the effect of acidic conditions on AdV particles by exploring their mechanical properties, genome accessibility and capsid disruption. Our results show that under short term acidification the AdV virion becomes softer and its genome less accessible to an intercalating dye, even in the presence of capsid openings. The AFM tip penetrates deeper in virions at neutral pH, and mechanical properties of genome-less particles are not altered upon acidification. Altogether, these results indicate that the main effect of acidification is the compaction of the nucleoproteic core, revealing a previously unknown role for chemical cues in AdV uncoating. Statement of significanceStudying the behavior of virus particles under changing environmental conditions is key to understand cell entry and propagation. One such change is the acidification undergone in certain cell compartments, which is thought to play a role in the programmed uncoating of virus genomes. Mild acidification in the early endosome has been proposed as a trigger signal for human AdV uncoating. However, the actual effect of low pH in AdV stability and entry is not well defined. Understanding the consequences of acidification in AdV structure and stability is also relevant to define storage conditions for therapeutic vectors, or design AdV variants resistant to intestinal conditions for oral administration of vaccines.

Oral Biologic Delivery: Advances Toward Oral Subunit, DNA, and mRNA Vaccines and the Potential for Mass Vaccination During Pandemics.

Oral vaccination enables pain-free and self-administrable vaccine delivery for rapid mass vaccination during pandemic outbreaks. Furthermore, it elicits systemic and mucosal immune responses. This protects against infection at mucosal surfaces, which may further enhance protection and minimize the spread of disease. The gastrointestinal (GI) tract presents a number of prospective mucosal inductive sites for vaccine targeting, including the oral cavity, stomach, and small intestine. However, currently available oral vaccines are effectively limited to live-attenuated and inactivated vaccines against enteric diseases. The GI tract poses a number of challenges,including degradative processes that digest biologics and mucosal barriers that limit their absorption. This review summarizes the approaches currently under development and future opportunities for oral vaccine delivery to established (intestinal) and relatively new (oral cavity, stomach) mucosal targets. Special consideration is given to recent advances in oral biologic delivery that offer promise as future platforms for the administration of oral vaccines.

Enhanced Oral Vaccine Efficacy of Polysaccharide-Coated Calcium Phosphate Nanoparticles.

Oral administration of vaccines has been limited due to low immune response compared to parenteral administration. Antigen degradation in the acidic gastrointestinal environment (GI), mucus barriers, and inefficient cellular uptake by immune cells are the major challenges for oral vaccine delivery. To solve these issues, the current study investigates calcium phosphate nanoparticles (CaP NPs) coated with polysaccharides as nanocarriers for oral protein antigen delivery. In this design, the CaP NP core had an optimized antigen encapsulation capacity of 90 mg (BSA-FITC)/g (CaP NPs). The polysaccharides chitosan and alginate were coated onto the CaP NPs to protect the antigens against acidic degradation in the GI environment and enhance the immune response in the small intestine. The antigen release profiles showed that alginate-chitosan-coated CaP NPs prevented antigen release in a simulated gastric fluid (pH 1.2), followed by sustained release in simulated intestinal (pH 6.8) and colonic (pH 7.4) fluids. Cellular uptake and macrophage stimulation data revealed that the chitosan coating enhanced antigen uptake by intestine epithelia cells (Caco-2) and macrophages and improved surface expression of costimulatory molecules on macrophages. In vivo test further demonstrated that oral administration of alginate-chitosan-coated CaP@OVA NPs significantly enhanced the mucosal IgA and serum IgG antibody responses as compared to naked OVA, indicating that the CaP-Chi-Alg nanoparticle can potentially be used as a promising oral vaccine delivery system.

Coding Hotline

This month's Coding Hotline addresses coding questions related to abnormal findings at a preventive visit, postoperative visits, and oral vaccine administration.

Variation in rotavirus vaccination coding in state US Medicaid data

Differences in state Medicaid policies and practices may result in variation in the recording of individual-level vaccination claims, which may present challenges for vaccination research using state Medicaid data. We describe differences in procedure coding for rotavirus vaccination in four states’ Medicaid programs by identifying rotavirus vaccine–specific codes and oral vaccine administration codes. The proportion of vaccinated children with vaccine-specific and oral vaccine administration codes differed substantially across states: two states used vaccine-specific codes almost exclusively (95.9% and 99.0%); one had exclusively oral vaccine administration codes (>99.9%); another had a mixture (32.1% vaccine-specific codes, 40.0% oral vaccine administration codes, and 27.9% both). Depending on the research question, studies using Medicaid data in states without (or with incomplete) vaccine-specific coding may be infeasible. Prior to initiating research, investigators should carefully evaluate state Medicaid policies and patterns of vaccination uptake, as vaccine reimbursement policies and availability of vaccine claims may vary.

An Oral Vaccination Method with the Aid of Capsaicin against Viral Nervous Necrosis (VNN)

To develop an oral vaccination method for viral nervous necrosis (VNN) caused by piscine nodavirus (betanodavirus), sevenband grouper Epinephelus septemfasciatus was immunized with inactivated redspotted grouper nervous necrosis virus (RGNNV) vaccine. ​Seven-day consecutive oral administration of the RGNNV vaccine via feed failed to induce protection in fish against the virus challenge at 21 days post-immunization. ​However, anal intubation of the vaccine conferred protective immunity on fish, although virus neutralizing antibodies could not be detected. Similar protective immunity was also confirmed by oral administration of vaccine via feed supplemented with capsaicin, suggesting that capsaicin modulated the intestinal mucosal barrier to induce immune response.

Preformulation studies with the Escherichia coli double mutant heat-labile toxin adjuvant for use in an oral vaccine

Double mutant heat-labile toxin (dmLT) is a promising adjuvant for oral vaccine administration. The aims of our study were to develop sensitive methods to detect low concentrations of dmLT and to use the assays in preformulation studies to determine whether dmLT remains stable under conditions encountered by an oral vaccine. We developed a sandwich ELISA specific for intact dmLT and a sensitive SDS-PAGE densitometry method, and tested stability of dmLT in glass and plastic containers, in saliva, at the pH of stomach fluid, and in high-osmolarity buffers. The developed ELISA has a quantification range of 62.5 to 0.9ng/mL and lower limit of detection of 0.3ng/mL; the limit of quantification of the SDS-PAGE is 10μg/mL. This work demonstrates the application of dmLT assays in preformulation studies to development of an oral vaccine containing dmLT. Assays reported here will facilitate the understanding and use of dmLT as an adjuvant.

Comparison of Immunologic Responses Following Intranasal and Oral Administration of a USDA-Approved, Live-Attenuated Streptococcus equi Vaccine

Although there is a commercially available vaccine for Streptococcus equi subspecies equi licensed for the intranasal (IN) route of administration, some equine practitioners are administering this vaccine orally despite a lack of evidence for its efficacy by this route of administration. The purpose of this study was to compare systemic and local immune responses following IN or oral administration of the United States Department of Agriculture (USDA)-approved, live-attenuated S. equi subspecies equi vaccine (Pinnacle IN; Zoetis, Florham Park, NJ). Eight healthy horses with low S. equi M protein (SeM) titers (<1:1,600) were randomly assigned to an IN or oral two-vaccine series. Streptococcus equi M protein–specific serum immunoglobulins G (IgG) and A (IgA) and nasal secretion IgA were assessed using a commercially available ELISA (SeM ELISA, Equine Diagnostics Solutions, LLC, Lexington, KY) and a novel magnetic microsphere assay utilizing fluorescence. A general linear mixed models approach was used for statistical data analysis. As expected, IN vaccinates showed substantial increases in both serum SeM-specific IgG and IgA levels postvaccination (P = .0006 and P = .007, respectively). Oral vaccinates showed an increase in serum SeM-specific IgG postvaccination (P = .0150), though only one third the magnitude of IN vaccinates. Oral vaccinates showed no evidence of change in SeM-specific IgA postvaccination (P = .15). Results indicate that IN or oral vaccine administration resulted in increased serum SeM-specific IgG, though the magnitude of response differed, where there was a 10-fold increase for IN vaccinates and only a threefold increase for oral vaccinates.