Evaluation of the Effect of Inactivated Transmissible Gastroenteritis Virus Vaccine with Nano Silicon on the Phenotype and Function of Porcine Dendritic Cells.

A transmissible gastroenteritis virus (TGEV) is a porcine enteropathogenic coronavirus, causing acute swine enteric disease especially in suckling piglets. Mesoporous silica nanoparticles (MSNs) are safe vaccine adjuvant, which could enhance immune responses. Our previous research confirmed that nano silicon had immune-enhancing effects with inactivated TGEV vaccine. In this study, we further clarified the immune-enhancing mechanism of the inactivated TGEV vaccine with MSNs on porcine dendritic cells (DCs). Our results indicated that the inactivated TGEV vaccine with MSNs strongly enhanced the activation of the DCs. Expressions of TLR3, TLR5, TLR7, TLR9, and TLR10, cytokines IFN-α, IL-1ß, IL-6, IL-12, and TNF-α, cytokine receptor CCR-7 of immature DCs were characterized and showed themselves to be significantly higher in the inactivated TGEV vaccine with the MSN group. In summary, the inactivated TGEV vaccine with MSNs has effects on the phenotype and function of porcine DCs, which helps to better understand the immune-enhancing mechanism.

Potential Therapeutic Targets and Vaccine Development for SARS-CoV-2/COVID-19 Pandemic Management: A Review on the Recent Update.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a highly pathogenic novel virus that has caused a massive pandemic called coronavirus disease 2019 (COVID-19) worldwide. Wuhan, a city in China became the epicenter of the outbreak of COVID-19 in December 2019. The disease was declared a pandemic globally by the World Health Organization (WHO) on 11 March 2020. SARS-CoV-2 is a beta CoV of the Coronaviridae family which usually causes respiratory symptoms that resemble common cold. Multiple countries have experienced multiple waves of the disease and scientific experts are consistently working to find answers to several unresolved questions, with the aim to find the most suitable ways to contain the virus. Furthermore, potential therapeutic strategies and vaccine development for COVID-19 management are also considered. Currently, substantial efforts have been made to develop successful and safe treatments and SARS-CoV-2 vaccines. Some vaccines, such as inactivated vaccines, nucleic acid-based, and vector-based vaccines, have entered phase 3 clinical trials. Additionally, diverse small molecule drugs, peptides and antibodies are being developed to treat COVID-19. We present here an overview of the virus interaction with the host and environment and anti-CoV therapeutic strategies; including vaccines and other methodologies, designed for prophylaxis and treatment of SARS-CoV-2 infection with the hope that this integrative analysis could help develop novel therapeutic approaches against COVID-19.

Does COVID-19 Vaccination Warrant the Classical Principle "ofelein i mi vlaptin"?

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic warrants an imperative necessity for effective and safe vaccination, to restrain Coronavirus disease 2019 (COVID-19) including transmissibility, morbidity, and mortality. In this regard, intensive medical and biological research leading to the development of an arsenal of vaccines, albeit incomplete preconditioned evaluation, due to emergency. The subsequent scientific gap raises some concerns in the medical community and the general public. More specifically, the accelerated vaccine development downgraded the value of necessary pre-clinical studies to elicit medium- and long-term beneficial or harmful consequences. Previous experience and pathophysiological background of coronaviruses' infections and vaccine technologies, combined with the global vaccines' application, underlined the obligation of a cautious and qualitative approach, to illuminate potential vaccination-related adverse events. Moreover, the high SARS-CoV-2 mutation potential and the already aggregated genetical alterations provoke a rational vagueness and uncertainty concerning vaccines' efficacy against dominant strains and the respective clinical immunity. This review critically summarizes existing evidence and queries regarding SARS-CoV-2 vaccines, to motivate scientists' and clinicians' interest for an optimal, individualized, and holistic management of this unprecedented pandemic.

Development of an Inactivated Vaccine Candidate, BBIBP-CorV, with Potent Protection against SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health. The development of a vaccine is urgently needed for the prevention and control of COVID-19. Here, we report the pilot-scale production of an inactivated SARS-CoV-2 vaccine candidate (BBIBP-CorV) that induces high levels of neutralizing antibodies titers in mice, rats, guinea pigs, rabbits, and nonhuman primates (cynomolgus monkeys and rhesus macaques) to provide protection against SARS-CoV-2. Two-dose immunizations using 2 µg/dose of BBIBP-CorV provided highly efficient protection against SARS-CoV-2 intratracheal challenge in rhesus macaques, without detectable antibody-dependent enhancement of infection. In addition, BBIBP-CorV exhibits efficient productivity and good genetic stability for vaccine manufacture. These results support the further evaluation of BBIBP-CorV in a clinical trial.

Porcine epidemic diarrhea vaccine efficacy evaluation by vaccination timing and frequencies.

Porcine epidemic diarrhea (PED) virus is a causative agent of enteric disease characterized by watery diarrhea and dehydration. Because PED has high morbidity and mortality, especially in suckling piglets, it causes a great economic loss to swine farms worldwide. Although various PED vaccines have been developed and commercialized, their efficacies are still controversial. In particular, current PED vaccination protocol (vaccination at 2 and 4 weeks before farrowing) may cause stress in pregnant sows. In this study, we compared the effects of PED vaccination timing and frequency for its efficacy by measuring the PED virus-specific antibodies. We found that vaccination at early stages of pregnancy induces similar levels of serum and colostrum antibodies with those at late stages of pregnancy. As the number of vaccinations increased, the amounts of antibody in serum and colostrum, and neutralizing activities increased. Our results provide important information for establishing a more efficient PED vaccination protocol.

The Taishan Robinia pseudoacacia polysaccharides enhance immune effects of rabbit haemorrhagic disease virus inactivated vaccines.

Robinia pseudoacacia flower, a common component in traditional Chinese medicine, has long been well-known for its high pharmaceutical value. This study aimed to assess the immunopotentiating effects of Taishan Robinia Pseudoacacia polysaccharides (TRPPS) in rabbits inoculated with a rabbit haemorrhagic disease virus (RHDV) inactivated vaccine. The rabbits were administered with the RHDV vaccine in conjunction with varying concentrations of TRPPS, and their blood samples were collected at different time points to analyze the ratio and number of blood lymphocytes. In addition, sera were prepared and analyzed to determine the overall antibody titer and the level of IL-2, a cytokine commonly used as an indicator of immune activity. The various TRPPS-supplemented vaccines were shown to be more effective in enhancing the immune functions of the inoculated rabbits compared to their polysaccharide-free counterpart, with 200 mg/mL of TRPPS exhibiting the most pronounced benefits that were comparable to those of propolis. In addition, the TRPPS-supplemented RHDV inactivated vaccines could significantly improve the survival rates of the immunized rabbits against RHDV infection. Our studies offered convincing experimental evidence for the development of TRPPS as a new type of plant-derived immunopotentiator.

Immunologic evaluation of 10 different adjuvants for use in vaccines for chickens against highly pathogenic avian influenza virus.

Avian influenza viruses (AIV) are a threat to poultry production worldwide. Vaccination is utilized as a component of control programs for both high pathogenicity (HP) and low pathogenicity (LP) AIV. Over 95% of all AIV vaccine used in poultry are inactivated, adjuvanted products. To identify the best formulations for chickens, vaccines were prepared with beta-propiolactone (BPL) inactivated A/British Columbia/314514-1/2004 H7N3 LP AIV using ten commercially available or experimental adjuvants. Each vaccine formulation was evaluated for immunogenicity in chickens. Challenge studies with an antigenically homologous strain of HPAIV were conducted to compare protection against mortality and measure reductions in virus levels in oral swabs. The four best adjuvants from the studies with BPL inactivated antigen were selected and tested identically, but with vaccines prepared from formalin inactivated virus. Mineral and vegetable oil based adjuvants generally induced the highest antibody titers with 100% seroconversion by 3weeks post vaccination. Chitosan induced positive antibody titers in 100% of the chickens, but the titers were significantly lower than those of most of the oil based adjuvants. Antibody levels from calcium phosphate and alginate adjuvanted groups were similar to those of non-adjuvanted virus. All groups that received adjuvanted vaccines induced similar levels of protection against mortality (0-20%) except the groups vaccinated with calcium phosphate adjuvanted vaccines, where mortality was similar (70%) to groups that received non-adjuvanted inactivated virus or no vaccine (60-100% mortality). Virus shedding in oral swabs was variable among the treatment groups. Formalin inactivated vaccine induced similar antibody titers and protection against challenge compared to BPL inactivated vaccine groups. These studies support the use of oil adjuvanted vaccines for use in the poultry industry for control for AIV.

Extrapolating theoretical efficacy of inactivated influenza A/H5N1 virus vaccine from human immunogenicity studies.

Influenza A virus subtype H5N1 has been a public health concern for almost 20years due to its potential ability to become transmissible among humans. Phase I and II clinical trials have assessed safety, reactogenicity and immunogenicity of inactivated influenza A/H5N1 virus vaccines. A shortage of vaccine is likely to occur during the first months of a pandemic. Hence, determining whether to give one dose to more people or two doses to fewer people to best protect the population is essential. We use hemagglutination-inhibition antibody titers as an immune correlate for avian influenza vaccines. Using an established relationship to obtain a theoretical vaccine efficacy from immunogenicity data from thirteen arms of six phase I and phase II clinical trials of inactivated influenza A/H5N1 virus vaccines, we assessed: (1) the proportion of theoretical vaccine efficacy achieved after a single dose (defined as primary response level), and (2) whether theoretical efficacy increases after a second dose, with and without adjuvant. Participants receiving vaccine with AS03 adjuvant had higher primary response levels (range: 0.48-0.57) compared to participants receiving vaccine with MF59 adjuvant (range: 0.32-0.47), with no observed trends in primary response levels by antigen dosage. After the first and second doses, vaccine with AS03 at dosage levels 3.75, 7.5 and 15mcg had the highest estimated theoretical vaccine efficacy: Dose (1) 45% (95% CI: 36-57%), 53% (95% CI: 42-63%) and 55% (95% CI: 44-64%), respectively and Dose (2) 93% (95% CI: 89-96%), 97% (95% CI: 95-98%) and 97% (95% CI: 96-100%), respectively. On average, the estimated theoretical vaccine efficacy of lower dose adjuvanted vaccines (AS03 and MF59) was 17% higher than that of higher dose unadjuvanted vaccines, suggesting that including an adjuvant is dose-sparing. These data indicate adjuvanted inactivated influenza A/H5N1 virus vaccine produces high theoretical efficacy after two doses to protect individuals against a potential avian influenza pandemic.

Effects of dietary L-glutamine supplementation on specific and general defense responses in mice immunized with inactivated Pasteurella multocida vaccine.

Little is known about effects of dietary glutamine supplementation on specific and general defense responses in a vaccine-immunized animal model. Thus, this study determined roles for dietary glutamine supplementation in specific and general defense responses in mice immunized with inactivated Pasteurella multocida vaccine. The measured variables included: (1) the production of pathogen-specific antibodies; (2) mRNA levels for pro-inflammatory cytokines, toll-like receptors and anti-oxidative factors; and (3) the distribution of P. multocida in tissues and the expression of its major virulence factors in vivo. Dietary supplementation with 0.5 % glutamine had a better protective role than 1 or 2 % glutamine against P. multocida infection in vaccine-immunized mice, at least partly resulting from its effects in modulation of general defense responses. Dietary glutamine supplementation had little effects on the production of P. multocida-specific antibodies. Compared to the non-supplemented group, dietary supplementation with 0.5 % glutamine had no effect on bacterial burden in vivo but decreased the expression of major virulence factors in the spleen. Collectively, supplementing 0.5 % glutamine to a conventional diet provides benefits in vaccine-immunized mice by enhancing general defense responses and decreasing expression of specific virulence factors.

A/H5N1 prepandemic influenza vaccine (whole virion, vero cell-derived, inactivated) [Vepacel®].

The influenza A subtype H5N1 virus is a likely causative agent for the next human influenza pandemic. Pandemic influenza vaccine production can begin only after a novel pandemic virus emerges. Cell-based vaccine production has advantages over conventional egg-based methods, allowing more rapid large-scale vaccine production. A reliable Vero cell culture system is available for pandemic and prepandemic influenza vaccine production. Prepandemic influenza vaccines are an important component of influenza pandemic preparedness plans, as their targeted use in the pandemic alert period or early in a pandemic is likely to mitigate the consequences of an influenza outbreak. Vepacel® is a prepandemic influenza vaccine (whole virion, Vero cell-derived, inactivated) containing antigen of H5N1 strain A/Vietnam/1203/2004 and is approved for use in the EU. Clinical immunogenicity studies with the vaccine have demonstrated good rates of functional neutralizing antibody responses against the vaccine strain (A/Vietnam/1203/2004), meeting established immunogenicity criteria for seasonal influenza vaccines, and cross-reactivity against H5N1 strains from other clades. In phase I/II and III studies, a heterologous (A/Indonesia/05/2005) booster vaccine administered to healthy adult and elderly volunteers 6-24 months after the two-dose priming vaccine (A/Vietnam/1203/2004) regimen induced good immunogenic responses against both H5N1 strains, demonstrating strong immunological memory. Broadly similar, albeit less robust, responses were observed in two special risk cohorts of immunocompromised and chronically ill patients. In general, adverse events observed in clinical immunogenicity studies with H5N1 vaccine (A/Vietnam/1203/2004) were similar to those reported with non-adjuvanted, inactivated, seasonal influenza vaccines.

Inactivated influenza vaccines: recent progress and implications for the elderly.

The current public health strategy for the containment of influenza is annual vaccination, which is recommended for the elderly and for those in risk factor categories that present the highest morbidity and mortality. However, because the immune response in the elderly is known to be less vigorous than in younger adults, research in the last decade has focused on improving the immune response to vaccination and increasing the protection of aged populations. The decreased efficacy of vaccines in the elderly is due to several factors, such as a decrease in the number of Langerhans cells, the limited capacity of dendritic cells to present antigen, defects in the expression of Toll-like receptors and the reduced expression of MHC class I and II molecules. Also, production of mature naive T cells by the thymus decreases with age. Among several approaches proposed to address the need for more immunogenic vaccines compared with conventional agents, the most well proven is the use of adjuvants. The first licensed adjuvant, aluminium-based mineral salts (alum), introduced in the 1920s, remains the standard worldwide adjuvant for human use and it has been widely used for almost a century. However, the addition of alum adjuvant to a split or subunit influenza vaccine has induced only marginal improvements. Other adjuvants have been developed and approved for human use since 1997; in particular, MF59, an oil-in-water adjuvant emulsion of squalene, which is able to increase immunogenicity of seasonal, pre-pandemic and pandemic subunit vaccines while maintaining acceptable safety and tolerability profiles. More recently, another oil-in-water emulsion, AS03, has been approved as a component of pre-pandemic H5N1 and pandemic H1N1 2009 vaccines. Besides adjuvants, several other strategies have been assessed to enhance antibody response in the elderly and other less responsive subjects, such as high-dose antigen vaccines, carrier systems (liposomes/virosomes) and the intradermal route of immunization. In particular, the potential of intradermal vaccination is well documented and the recent availability of an appropriate injection system, which combines simplicity, safety and ease of use, has allowed evaluation of the tolerability, safety and immunogenicity of the intradermal influenza vaccine in large numbers of subjects. Data that emerged from large clinical trials showed an improved immunogenicity compared with that of standard vaccine. Observational studies or comparisons between adjuvanted, intradermal or high-dose versus conventional vaccines are needed to evaluate whether the greater immunogenicity observed in a number of recent studies is correlated with greater protection against influenza and influenza-related complications and death.

Quantification of water buffalo (Bubalus bubalis) cytokine expression in response to inactivated foot-and-mouth disease (FMD) vaccine.

This study describes the quantification of cytokine expression of vaccinated water buffaloes with FMD inactivated vaccine. Using real-time PCR quantification assay, expression of Th1 (IL-2, IL-12p40, IFNgamma); Th2 (IL-4, IL-10) and inflammatory (IL-6, TNFalpha) cytokines were quantified weekly for the entire three-week duration of the experiment. It was noted that IFNgamma, IL-10 and TNFalpha had peaked on week three post-vaccination while the remaining cytokines peaked on the second week and decreased by the third week. The counteraction between IFNgamma and IL-4 was noted as well as the possible suppressive action of IL-10 to that of IL-2 and IL-12, which is a common phenomenon between Th1 and Th2 cytokines. Synergy between TNFa and IL-6 was also observed. These findings suggest that within the immune system of water buffalo there is a dynamic cell-mediated and humoral interaction in response to immunogen. This assessment of the cytokine expressions is vital for the study of water buffalo disease progression and concurring protective immune responses.

Enhanced immunogenicity of an oral inactivated cholera vaccine in infants in Bangladesh obtained by zinc supplementation and by temporary withholding breast-feeding.

The killed oral cholera vaccine Dukoral is recommended for adults and only children over 2 years of age, although cholera is seen frequently in younger children and there is an urgent need for a vaccine for them. Since decreased immunogenicity of oral vaccines in children in developing countries is a critical problem, we tested interventions to enhance responses to Dukoral. We evaluated the effect on the immune responses by temporarily withholding breast-feeding or by giving zinc supplementation. Two doses of Dukoral consisting of killed cholera vibrios and cholera B subunit were given to 6-18 months old Bangladeshi children (n=340) and safety and immunogenicity studied. Our results showed that two doses of the vaccine were safe and induced antibacterial (vibriocidal) antibody responses in 57% and antitoxin responses in 85% of the children. Immune responses were comparable after intake of one and two doses. Temporary withholding breast-feeding for 3 h before immunization or supplementation with 20 mg of zinc per day for 42 days resulted in increased magnitude of vibriocidal antibodies (77% and 79% responders, respectively). Administration of vaccines without buffer or in water did not result in reduction of vibriocidal responses. This study demonstrates that the vaccine is safe and immunogenic in children under 2 years of age and that simple interventions can enhance immune responses in young children.

An oil-emulsion vaccine induces full-protection against Mycoplasma agalactiae infection in sheep.

The immunogenicity and efficacy of three inactivated vaccines (A, B, C) prepared with Mycoplasma agalactiae (M. agalactiae) and with different oil-emulsion adjuvants were evaluated in sheep. Twenty-eight animals were used, divided into four groups (a, b, c, d) of seven animals each. Three groups were immunized with the same vaccine, but using different adjuvants, while one group (d) was used as an unvaccinated control group. All the vaccine formulations were able to induce clinical protection of animals after challenge with M. agalactiae, but only vaccine C, emulsioned with Montanide ISA-563, Marcol-52 and Montane-80 (ratio: 30%, 63%, 7% respectively), was able to induce full protection in challenged animals, preventing both the onset of clinical signs and infection by M. agalactiae.

Transcutaneous immunization with inactivated influenza virus induces protective immune responses.

The recent outbreaks of highly pathogenic avian influenza in Asia and spread of the disease worldwide highlight the need to redefine conventional immunization approaches and establish effective mass vaccination strategies to face global pandemics. Transcutaneous immunization (TCI) is a novel route for vaccination, which uses the topical application of vaccine antigens on the skin. In this study, we investigated the potential of TCI using inactivated whole influenza virus. We found that TCI with whole inactivated influenza virus induced influenza virus-specific antibodies with hemagglutination inhibition and neutralizing activities as well as cellular immune responses, even without an adjuvant, and conferred protective immunity to virus challenge. Co-administration with cholera toxin (CT), a potent adjuvant for TCI, significantly enhanced immune responses against the influenza virus antigen. To enhance penetration of the skin barrier to the particulate influenza viral antigens, we tested the effects of the potential penetration enhancers/immunomodulators oleic acid (OA) and retinoic acid (RA). Pretreatment of mouse skin with OA elicited increased levels of influenza virus-specific binding and neutralizing antibodies to levels equivalent to those induced by intranasal immunization with inactivated influenza virus. OA and RA treatments differentially affected the pattern of cytokine production upon stimulation with influenza viral antigen and provided enhanced protection. These results reveal a promising perspective for the application of transcutaneous immunization to prevent influenza epidemics as well as a range of other infectious diseases.

Does immunotherapy with heat-killed Mycobacterium vaccae offer hope for the treatment of multi-drug-resistant pulmonary tuberculosis?

The ability of immunotherapy with heat-killed Mycobacterium vaccae (NCTC 11659), as an addition to the available chemotherapy, to improve the outcome in patients with multi-drug-resistant tubercle bacilli (MDRTB) who had not been cured by chemotherapy alone was evaluated in tuberculosis centres in Estonia, Iran, Kuwait, New Zealand, Romania, Vietnam and the U.K. A total of 337 patients in the above countries received intradermal injections of M. vaccae in addition to chemotherapy. Patients were grouped according to the length of their histories of disease: less than or greater than 2 years duration. Initially, single doses of M. vaccae were given but subsequently up to 12 doses at 2-month intervals were given. Chemotherapy varied from isoniazid alone to drugs selected according to susceptibility tests. Most patients had failed to respond to repeated courses of chemotherapy and the majority, were expected to die from their disease. Results were assessed by sputum smear and culture and by clinical observations. Cured patients were followed for 18-24 months to exclude relapse. Eighteen of 22 (82%) patients with disease for less than 2 years were bacteriologically cured by one or two doses of M. vaccae. Among 315 chronic patients, 24 (7.6%) were cured after one dose, 37.9% after seven doses and 41.6% after 12 doses. Sixty-six chronic patients were lost to follow-up, or died, during the multi-dose regimens. Nine of 33 patients (27%) with advanced disease unaffected by several courses of chemotherapy and discharged on isoniazid alone in Vietnam were cured by 3-12 injections of M. vaccae. The data provide preliminary evidence that the addition of immunotherapy with M. vaccae to chemotherapy improves the rate of cure of MDRTB, most effectively in patients with short histories of disease, but multiple dosing can have beneficial effects in chronic patients in whom chemotherapy has failed. A randomized clinical trial of this immunotherapy in MDRTB patients is therefore required.

[The effects of small dosage inactivated BCG vaccine on cellular immune function of pulmonary chronic obstructive disease patients with deficiency of lung-qi].

UNLABELLED: To investigate the effects of the small dosage inactivated BCG vaccine on the cellular immune function of the patients suffered from pulmonary chronic obstructive disease with deficiency of the Lung-Qi, the authors observed the patients' immune function before and after BCG treatment for half a year. RESULTS: The peripheral blood T lymphocytes subsefs (CD3, CD4, CD8, CD4/CD8) and the conversion ratio of lymphocyte of the patients both were significantly lower than those of the healthy people (P < 0.01). But after the treatment of the small dosage inactivated BCG vaccine for half a year, these parameters of the patients were improved (P < 0.01 or P < 0.05). It indicated that the small dosage inactivated BCG vaccine could improve the damaged cellular immune function.

An inactivated vaccine against ringworm.

A new vaccine against ringworm, containing the inactivated Trichophyton verrucosum strain, was assessed on guinea pigs and calves under experimental conditions and on three herds of cattle under natural conditions. The vaccine elicited a distinct immune response of the cellular type. This type of immunity assessed by the migration inhibition test of leukocytes corresponded to the immunity evaluated by the challenge. In herds in which there were from 30 to 67% of naturally infected animals with T. verrucosum, two doses of the vaccine resulted in after 4 weeks a decrease of the number of animals with clinical changes from 40.5 to 100% depending on the group of animals under study.

Further comparison of adjuvants for an inactivated infectious coryza vaccine.

Inactivated infectious coryza vaccines containing different adjuvants were administered to 6-week-old chickens as a single dose containing 10(8) colony-forming units of Haemophilus paragallinarum HP31. After 3 weeks, all chickens were challenged by intrasinus inoculation of HP31. Two vaccines, one containing an aluminum-hydroxide adjuvant and the other a combined aluminum-hydroxide + avridine (a lipoidal amine) adjuvant, were effective. The three remaining vaccines--containing mineral-oil double-emulsion, avridine, or a combination of mineral-oil double-emulsion + avridine--gave much lower levels of protection. No adverse reactions were seen with any vaccine.