Aluminum Hydroxide Adjuvant Research Articles

Prototype Pentavalent Bovine Leptospira Vaccines Blended with Oil Adjuvant Provides Protection and Prevents Renal Colonization in Guinea Pig Model

Background: Leptospirosis significantly impacts the economy of livestock farmers by causing reproductive failure and production losses in bovines. The control of bovine leptospirosis requires a combination of vaccination programme, biosecurity measures and chemotherapeutic regimens. Vaccination protect the clinical diseases and reduces/prevents renal colonisation of Leptospires and in turn reduces excretion of leptospires in urine which is a major source of environmental contamination. Some serovars of leptospires require cell mediated immunity apart from humoral immunity. This study was undertaken to develop prototype vaccine with prevalent serogroups to induce humoral and cell mediated immunity. Immunogenicity of the prototype vaccines and their safety were assessed experimentally in Guinea pigs.Methods: An inactivated oil adjuvant prototype pentavalent bovine leptospira vaccines with serogroups Australis, Hebdomadis, Hardjo, Javanica and Pomona which were prevalent in Tamil Nadu were developed and compared with the aluminium hydroxide gel adjuvant vaccine. The humoral immune response was assessed measuring antibodies by Microscopic Agglutination Test and Cell Mediated Immune response was assessed by lymphocyte proliferation assay. The ability of these vaccines to protect Guinea pigs against virulent Leptospires challenge was also demonstrated.Result: The prototype vaccine blended with oil adjuvants resulted in higher protective antibody titres of more than 6.64 log2 (≥1:100) than the aluminium hydroxide adjuvant blended vaccine. The protective antibody titres lasted upto 180 days, except for serogroup Javanica (150 days). The Montanide adjuvants were able to produce cell mediated immune response for protection against serovar Hardjo. Challenge study in guinea pigs showed complete protection following vaccination using pentavalent vaccine blended with Montanide adjuvants, while the aluminium hydroxide adjuvant was able to confer only partial protection. The Montanide blended prototype vaccines were also able to prevent renal colonisation of all five serogroups. This study shows the potential of the oil adjuvant blended multivalent vaccine for use in vaccination programmes against bovine leptospirosis.

The Immunogenicity of Capsid-Like Particle Vaccines in Combination with Different Adjuvants Using Different Routes of Administration.

Capsid-like particle (CLP) displays can be used to enhance the immunogenicity of vaccine antigens, but a better understanding of how CLP vaccines are best formulated and delivered is needed. This study compared the humoral immune responses in mice elicited against two different vaccine antigens (a bacterial protein and a viral peptide) delivered on an AP205 CLP platform using six different adjuvant formulations. In comparison to antibody responses obtained after immunization with the unadjuvanted CLP vaccine, three of the adjuvant systems (neutral liposomes/monophosphoryl lipid A/quillaja saponaria 21, squalene-in-water emulsion, and monophosphoryl lipid A) caused significantly increased antibody levels, whereas formulation with the three other adjuvants (aluminum hydroxide, cationic liposomes, and cationic microparticles) resulted in similar or even decreased antibody responses. When delivering the soluble bacterial protein in a squalene-in-water emulsion, 4-log lower IgG levels were obtained compared to when the protein was delivered on CLPs without the adjuvant. The AP205 CLP platform promoted induction of both IgG1 and IgG2 subclasses, which could be skewed towards a higher production of IgG1 (aluminum hydroxide). Compared to other routes, intramuscular administration elicited the highest IgG levels. These results indicate that the effect of the external adjuvant does not always synergize with the adjuvant effect of the CLP display, which underscores the need for empirical testing of different extrinsic adjuvants.

Preclinical safety and immunogenicity of Streptococcus pyogenes (Strep A) peptide vaccines

We have developed two candidate vaccines to protect against multiple strains of Strep A infections. The candidates are combinatorial synthetic peptide vaccines composed of a M protein epitope (J8 or p*17) and a non-M protein epitope (K4S2). To enhance immunogenicity, each peptide is conjugated to the carrier protein CRM197 (CRM) and formulated with aluminium hydroxide adjuvant Alhydrogel (Alum) to make the final vaccines, J8-CRM + K4S2-CRM/Alum and p*17-CRM + K4S2-CRM/Alum. The safety and toxicity of each vaccine was assessed. Sprague Dawley rats were administered three intramuscular doses, over a six-week study with a 4-week recovery period. A control group received CRM only formulated with Alum (CRM/Alum). There was no evidence of systemic toxicity in the rats administered either vaccine. There was an associated increase in white blood cell, lymphocyte and monocyte counts, increased adrenal gland weights, adrenocortical hypertrophy, and increased severity of granulomatous inflammation at the sites of injection and the associated inguinal lymph nodes. These changes were considered non-adverse. All rats administered vaccine developed a robust and sustained immunological response. The absence of clinical toxicity and the development of an immunological response in the rats suggests that the vaccines are safe for use in a phase 1 clinical trial in healthy humans.

Safety and Immunogenicity of Nanocovax, a SARS-CoV-2 Recombinant Spike Protein Vaccine

Background: Nanocovax is a recombinant severe acute respiratory syndrome coronavirus 2 subunit vaccine composed of full-length prefusion stabilized recombinant SARS-CoV-2 spike glycoproteins (S-2P) and aluminum hydroxide adjuvant.Methods: We conducted a dose-escalation, open label trial (phase 1) and a randomized, double-blind, placebo-controlled trial (phase 2) to evaluate the safety and immunogenicity of the Nanocovax vaccine (in 25 microgram (mcg), 50 mcg, and 75 mcg doses, aluminum hydroxide adjuvanted). In phase 1, 60 participants received two intramuscular injection of the vaccine following dose-escalation procedure. The primary outcomes were reactogenicity and laboratory tests to evaluate the vaccine safety. In phase 2 which involved in 560 healthy adults, the primary outcomes are vaccine safety, and anti-S IgG antibody response. Secondary outcomes were surrogate virus neutralization, wild-type SARS-CoV-2 neutralization, and T-cell responses by intracellular staining (ICS) for interferon gamma (IFNg). Anti-S IgG and neutralizing antibody levels were compared with convalescent serum samples from symptomatic Covid-19 patients.Findings: For phase 1 study, no serious adverse events (SAE) were observed for all 60 participants. Most adverse events (AE) were grade 1 and disappeared shortly after injection. For phase 2 study, after randomization, 480 participants were assigned to receive the vaccine with adjuvant, and 80 participants were assigned to receive placebo. Reactogenicity was absent or mild in the majority of participants and of short duration (mean ≤3 days). Unsolicited adverse events were mild in most participants. There were no serious adverse events related to Nanocovax. Regarding the immunogenicity, Nanocovax induced robust anti-S antibody responses. In general, there humoral responses were similar among vaccine groups up to day 90. Anti S-IgG levels and neutralizing antibody titers at the peak response on day 42 were all higher than those of convalescent sera.Interpretation: Up to day 90, Nanocovax was found to be safe, well tolerated, and induced robust immune responses. 25 mcg was selected for a phase 3 trial to evaluate the vaccine efficacy.Trial Registration: ClinicalTrials.gov number, NCT04683484. NCT04683484, registration date in clinicaltrial.gov is Dec24, 2020, We has started our Phase 1 clinical trial in Vietnam on Dec 17, 2020,Funding: Research funded by Nanogen Pharmaceutical Biotechnology JSC., and the Ministry of Science and Technology of VietnamDeclaration of Interest: The following authors Thuy Phuong Nguyen, Hiep Khong, Tri Minh Le, Tuyen Thi Ngoc Trang, Thanh Thi Dinh, Thuong Van Vo, Thao Thi Thu Vu, Quynh Bao Phuong Nguyen, Vuong Tan Phan, Vinh The Tran, Mai Thi Nhu Tran, Truc Thi Thanh Nguyen, Phat Tan Ha, Hieu Trong Huynh, Khanh Duy Nguyen, Chung Chinh Doan, Thuan Trong Ung, Si Minh Do are employees of Nanogen Pharmaceutical Biotechnology JSC. All other authors declare no competing interests.Ethical Approval: The trials were designed and funded by Nanogen Pharmaceutical Biotechnology JSC and the Ministry of Science and Technology (MOST) of Vietnam. The trial protocol was approved by the Ethics Committee/Protocol Review Board of the Ministry of Health (Vietnam)

Safety, Tolerability and Immunogenicity of an Inactivated SARS-CoV-2 Vaccine (CoronaVac) in Healthy Children and Adolescents: A Randomised, Double-Blind, and Placebo-Controlled, Phase 1/2 Clinical Trial

Background: The COVID-19 vaccine for children and adolescents, who are indispensable populations to curb the pandemic, would protect this population against rare severe COVID-19 and infectious conditions. Here we aimed to assess the safety, tolerability and immunogenicity of a candidate COVID-19 vaccine, CoronaVac, containing inactivated SARS-CoV-2, in children and adolescents aged 3-17 years old. Methods: We did a randomised, double-blind, placebo-controlled phase 1/2 clinical trial of CoronaVac in healthy children and adolescents aged 3-17 years old in Zanhuang (Hebei, China). Vaccine (in 0 ·5ml aluminum hydroxide adjuvant) or placebo (adjuvant only) was given by intramuscular injection in two doses (day 0 and day 28). We conducted phase 1 trial in 71 participants with an age de-escalation in tree groups and dose-escalation in two blocks (1.5ug or 3ug per injection). Within each block, participants were randomly assigned (3:1) using block randomisation to receive CoronaVac or placebo. In phase 2, participants were randomly assigned (2:2:1) using block randomisation to receive either CoronaVac at 1.5ug or 3ug per dose, or placebo. The primary safety endpoint was adverse reactions within 28 days after each injection in all participants who received at least one dose. The primary immunogenicity endpoint was seroconversion rate at 28 days after the second injection and its GMT as the secondary endpoint. This study is ongoing and is registered with ClinicalTrials.gov (NCT04551547).Findings: Between October 31 and December 2, 2020, 72 participants were enrolled in phase 1, and between December 12 and December 30, 2020, 480 participants were enrolled in phase 2. 500 participants received at least one dose of vaccine or placebo (n=71 for phase 1 and n=479 for phase 2; safety population). In the combined safety profile of phase 1 and phase 2, any adverse reactions within 28 days after injection occurred in 56 (26%) of 219 participants in the 1·5ug group, 63 (29%) of 217 in the 3ug group and 27 (24%) of 114 in the placebo group, without significant difference. Most adverse reactions were mild and moderate in severity and injection site pain (73[13%]) of 550 participants was the most frequently reported event. As of March 12, 2021, only one serious adverse event has been reported, which was considered unrelated to vaccination. In phase 1, seroconversion after the second dose was observed in 27 of 27 participants (100·0% [95%CI 87·3-100·0]) in the 1·5ug groups and 26 of 26 participants (100·0% [86·8-100·0]) in the 3ug group, with the geometric mean titers of 55·0 (95%CI 38·9-77·9) and 117·4 (87·8-157·0). In phase 2, seroconversion was seen in 180 of 186 participants (96·8% [93·1-98·8]) in the 1·5ug group and 180 of 180 participants (100·0% [98·0-100·0]) in the 3ug group, with the geometric mean titers of 86·4 (73·9-101·0) and 142·2 (124·7-162·1). There were no detectable antibody responses in the placebo groups. Interpretation: CoronaVac was well tolerated and induced strong neutralising antibody responses in children and adolescents aged 3-17 years. The study has provided solid safety and immunogenicity data to support the further study and use of CoronaVac in children and adolescents.Trial Registration: NCT04551547Funding Statement: Chinese National Key Research and Development Program and Beijing Science and Technology Program.Declaration of Interests: QG and XL are employees of Sinovac Life Sciences Co., Ltd. YS, WY and LW are employees of Sinovac Biotech Ltd. All other authors declare no competing interests.Ethics Approval Statement: The clinical trial protocol and informed consent form were approved by the Ethics Committee of Hebei CDC (IRB2020-005).

Cloning and expression of Neospora caninum rhoptry 2 and its potential as an immunobiological for neosporosis control

ABSTRACT: The protozoan Neospora caninum is known worldwide as one of the main causes of abortion in cattle. During infection, rhoptry proteins present in the apical complex of the parasite play important roles in adhesion and parasitophorous vacuole formation. The use of N. caninum ROP2 in experimental vaccines has shown promising protective results. In our study we performed cloning and expression in Escherichia coli of an antigenic portion of N. caninum ROP2. The recombinant protein (rROP2) was obtained in insoluble form, and the purified protein showed a size of approximately 18kDa. Even being a small truncate NcROP2 region, it was possible to conserve the antigenic epitopes which were recognized by bovine serum naturally infected with N. caninum. Vaccination with rROP2 on aluminum hydroxide adjuvant induced high levels of rROP2-specific IgG antibodies capable of recognizing native protein in tachyzoite lysates. In conclusion, our approaches were effective in obtaining the rROP2 protein, which induced specific mouse immune response and was also recognized by sera from N. caninum naturally infected cattle. These results suggest that it is a promising antigen for the development of neosporosis subunit vaccines as well as a suitable antigen for use in immunodiagnosis.

Therapeutic effects and mechanisms study of Hanchuan Zupa Granule in a Guinea pig model of cough variant asthma

Ethnopharmacological relevanceHanchuan Zupa Granule (HCZP), a traditional Chinese ethnodrug, has the functions of supressing a cough, resolving phlegm, warming the lungs, and relieving asthma. In clinical practice employing traditional Chinese medicine (TCM), HCZP is commonly used to treat acute colds, cough and abnormal mucous asthma caused by a cold, or “Nai-Zi-Lai” in the Uygur language. Studies have confirmed the use of HCZP to treat cough variant asthma (CVA) and other respiratory diseases. However, the pharmacological mechanisms of HCZP remain unrevealed. Aim of the studyTo investigate the anti-tussive and anti-asthmatic effects and the possible pharmacological mechanisms of HCZP in the treatment of CVA. Materials and methodsA guinea pig CVA animal model was established by intraperitoneal injection of ovalbumin (OVA) combined with intraperitoneal injection of aluminium hydroxide adjuvant and atomized OVA. Meanwhile, guinea pigs with CVA received oral HCZP (at dosages of 0.571, 0.285 and 0.143 g/kg bodyweight). The number of coughs induced by aerosol capsaicin was recorded, and the airway hyperresponsiveness (AHR) of CVA guinea pigs was detected with the FinePointe series RC system. H&E staining of lung tissues was performed to observe pathological changes. ELISA was used to detect inflammatory cytokines. qRT-PCR and western blotting analyses were used to detect the expression of Th1-specific transcription factor (T-bet), Th2-specific transcription factor (GATA3), and Toll-like receptor 4 (TLR4) signal transduction elements. These methods were performed to assess the protective effects and the potential mechanisms of HCZP on CVA. ResultsGreat changes were found in the CVA guinea pig model after HCZP treatment. The number of coughs induced by capsaicin in guinea pigs decreased, the body weights of guinea pigs increased, and inflammation of the eosinophilic airway and AHR were reduced simultaneously. These results indicate that HCZP has a significant protective effect on CVA. A pharmacological study of HCZP showed that the levels of interleukin-4 (IL-4) and IL-5 and tumour necrosis factor-α (TNF-α) in serum decreased. The amount of interferon-γ (IFN-γ) increased, mRNA and protein expression of TLR4 and GATA3 weakened, and mRNA and protein expression of T-bet increased. ConclusionsHCZP ameliorated the symptoms of guinea pigs with CVA induced by OVA by regulating the Th1/Th2 imbalance and TLR4 receptors.

Optimization of RG1-VLP vaccine performance in mice with novel TLR4 agonists

Current human papilloma virus (HPV) vaccines provide substantial protection against the most common HPV types responsible for oral and anogenital cancers, but many circulating cancer-causing types remain that lack vaccine coverage. The novel RG1-VLP (virus-like particle) vaccine candidate utilizes the HPV16-L1 subunit as a backbone to display an inserted HPV16-L2 17–36 a.a. “RG1” epitope; the L2 RG1 epitope is conserved across many HPV types and the generation of cross-neutralizing antibodies (Abs) against which has been demonstrated. In an effort to heighten the immunogenicity of the RG1-VLP vaccine, we compared in BALB/c mice adjuvant formulations consisting of novel bacterial enzymatic combinatorial chemistry (BECC)-derived toll-like receptor 4 (TLR4) agonists and the aluminum hydroxide adjuvant Alhydrogel. In the presence of BECC molecules, consistent improvements in the magnitude of Ab responses to both HPV16-L1 and the L2 RG1 epitope were observed compared to Alhydrogel alone. Furthermore, neutralizing titers to HPV16 as well as cross-neutralization of pseudovirion (PsV) types HPV18 and HPV39 were augmented in the presence of BECC agonists as well. Levels of L1 and L2-specific Abs were achieved after two vaccinations with BECC/Alhydrogel adjuvant that were equivalent to or greater than levels achieved with 3 vaccinations with Alhydrogel alone, indicating that the presence of BECC molecules resulted in accelerated immune responses that could allow for a decreased dose schedule for VLP-based HPV vaccines. In addition, dose-sparing studies indicated that adjuvantation with BECC/Alhydrogel allowed for a 75% reduction in antigen dose while still retaining equivalent magnitudes of responses to the full VLP dose with Alhydrogel. These data suggest that adjuvant optimization of HPV VLP-based vaccines can lead to rapid immunity requiring fewer boosts, dose-sparing of VLPs expensive to produce, and the establishment of a longer-lasting humoral immunity.

Immunogenicity and safety of an adjuvanted inactivated polio vaccine, IPV-Al, in primary and booster trials in Asia, Central America and Europe

Background: Withdrawal of OPV and the widespread introduction of IPV is key in the Polio Endgame Strategy. This transition from OPV to IPV requires more and affordable IPV in quantities sufficient to secure at least two doses of IPV for every child. An adjuvanted inactivated polio vaccine (IPV-Al), obtained by adsorption of a reduced dose of inactivated poliovirus to an aluminium hydroxide adjuvant, can help mitigate global supply and cost constraints of IPV through dose-sparing. Aim: Investigation of immunogenicity and safety of IPV-Al compared to standard IPV: Methods and materials: Two primary vaccination phase 3 trials in infants vaccinated at 6, 10, 14 weeks and 9 months in the Philippines; at 2, 4, 6 months and 15–18 months in Panama. A Phase 2 primary vaccination trial in the Dominican Republic in infants vaccinated at 6, 10, 14 weeks. A Phase 1/2 booster vaccination trial in Denmark in children and adolescents (10–15 years) with a history of standard IPV vaccination. Results: Seroconversion rates (an antibody titre ≥4-fold higher than the estimated maternal antibody titre and a titre ≥8) evaluated one month after primary vaccination were: polio type 1, 96–98% (IPV-Al) versus 99–100% (IPV); type 2, 94–100% versus 99–100%; and type 3, 98–99% versus 99–100%. Non-inferiority of IPV-Al to IPV (predefined 10%-point margin) was confirmed in trials assessing primary immunogenicity. In infants, robust booster responses were demonstrated following a fourth polio vaccination and post-booster geometric mean titres (GMTs) were higher than post-priming GMTs. In the adolescent trial, robust booster responses were demonstrated following a fifth polio vaccination. IPV-Al was well tolerated with a safety profile comparable to that of standard IPV in the three trials. Conclusion: IPV-Al was demonstrated to be non-inferior to standard IPV for seroconversion following primary vaccination in the EPI schedule in Philippines and Dominican Republic, and at 2, 4, 6 months in Panama. Robust post-booster responses in 9-month-olds, 15–18-month-olds and 10–15-year-olds were demonstrated for IPV-Al. IPV-Al was safe and well tolerated. Results support the applicability of the dose-sparing adjuvanted IPV-Al vaccine to help secure a more affordable and stable supply of IPV for prevention of poliomyelitis as part of the global polio eradication initiative.

Whole transcriptome approach to evaluate the effect of aluminium hydroxide in ovine encephalon

Aluminium hydroxide adjuvants are crucial for livestock and human vaccines. Few studies have analysed their effect on the central nervous system in vivo. In this work, lambs received three different treatments of parallel subcutaneous inoculations during 16 months with aluminium-containing commercial vaccines, an equivalent dose of aluminium hydroxide or mock injections. Brain samples were sequenced by RNA-seq and miRNA-seq for the expression analysis of mRNAs, long non-coding RNAs and microRNAs and three expression comparisons were made. Although few differentially expressed genes were identified, some dysregulated genes by aluminium hydroxide alone were linked to neurological functions, the lncRNA TUNA among them, or were enriched in mitochondrial energy metabolism related functions. In the same way, the miRNA expression was mainly disrupted by the adjuvant alone treatment. Some differentially expressed miRNAs had been previously linked to neurological diseases, oxidative stress and apoptosis. In brief, in this study aluminium hydroxide alone altered the transcriptome of the encephalon to a higher degree than commercial vaccines that present a milder effect. The expression changes in the animals inoculated with aluminium hydroxide suggest mitochondrial disfunction. Further research is needed to elucidate to which extent these changes could have pathological consequences.

Effect of an Inactivated Vaccine Against SARS-CoV-2 on Safety and Immunogenicity Outcomes

A vaccine against coronavirus disease 2019 (COVID-19) is urgently needed. To evaluate the safety and immunogenicity of an investigational inactivated whole-virus COVID-19 vaccine in China. In the phase 1 trial, 96 participants were assigned to 1 of the 3 dose groups (2.5, 5, and 10 μg/dose) and an aluminum hydroxide (alum) adjuvant-only group (n = 24 in each group), and received 3 intramuscular injections at days 0, 28, and 56. In the phase 2 trial, 224 adults were randomized to 5 μg/dose in 2 schedule groups (injections on days 0 and 14 [n = 84] vs alum only [n = 28], and days 0 and 21 [n = 84] vs alum only [n = 28]). Interim analysis of ongoing randomized, double-blind, placebo-controlled, phase 1 and 2 clinical trials to assess an inactivated COVID-19 vaccine. The trials were conducted in Henan Province, China, among 96 (phase 1) and 224 (phase 2) healthy adults aged between 18 and 59 years. Study enrollment began on April 12, 2020. The interim analysis was conducted on June 16, 2020, and updated on July 27, 2020. The primary safety outcome was the combined adverse reactions 7 days after each injection, and the primary immunogenicity outcome was neutralizing antibody response 14 days after the whole-course vaccination, which was measured by a 50% plaque reduction neutralization test against live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among 320 patients who were randomized (mean age, 42.8 years; 200 women [62.5%]), all completed the trial up to 28 days after the whole-course vaccination. The 7-day adverse reactions occurred in 3 (12.5%), 5 (20.8%), 4 (16.7%), and 6 (25.0%) patients in the alum only, low-dose, medium-dose, and high-dose groups, respectively, in the phase 1 trial; and in 5 (6.0%) and 4 (14.3%) patients who received injections on days 0 and 14 for vaccine and alum only, and 16 (19.0%) and 5 (17.9%) patients who received injections on days 0 and 21 for vaccine and alum only, respectively, in the phase 2 trial. The most common adverse reaction was injection site pain, followed by fever, which were mild and self-limiting; no serious adverse reactions were noted. The geometric mean titers of neutralizing antibodies in the low-, medium-, and high-dose groups at day 14 after 3 injections were 316 (95% CI, 218-457), 206 (95% CI, 123-343), and 297 (95% CI, 208-424), respectively, in the phase 1 trial, and were 121 (95% CI, 95-154) and 247 (95% CI, 176-345) at day 14 after 2 injections in participants receiving vaccine on days 0 and 14 and on days 0 and 21, respectively, in the phase 2 trial. There were no detectable antibody responses in all alum-only groups. In this interim report of the phase 1 and phase 2 trials of an inactivated COVID-19 vaccine, patients had a low rate of adverse reactions and demonstrated immunogenicity; the study is ongoing. Efficacy and longer-term adverse event assessment will require phase 3 trials. Chinese Clinical Trial Registry Identifier: ChiCTR2000031809.

Efficacy of two adjuvants administrated with a novel hydrogen peroxide-inactivated vaccine against Streptococcus agalactiae in Nile tilapia fingerlings

Streptococcus agalactiae is considered the main bacterial pathogen in cultured Nile tilapia. Formaldehyde-inactivated vaccines are the most accepted method for prevention and control of the disease. However, alternative inactivation methods for S. agalactiae vaccines have not been fully explored. Recently, we developed a hydrogen peroxide-inactivated vaccine against S. agalactiae with moderate efficacy, with the possibility to improve vaccine efficacy by adding adjuvants. The current study compared the efficacy of aluminum hydroxide and Freund's incomplete adjuvant (FIA) incorporated into a novel hydrogen peroxide-inactivated intraperitoneal vaccine against S. agalactiae for Nile tilapia fingerlings. The relative percentage survival (RPS) for aluminum hydroxide-adjuvanted vaccine (59.3%), and FIA-adjuvanted vaccine (77.8%) were higher than the vaccine without adjuvant (40.7%). In addition, fish immunized with aluminum hydroxide-adjuvanted vaccine had significantly higher levels of specific antibodies than control fish at 4 weeks post vaccination (wpv). Blood lymphocytes counts showed a decrease in vaccinated groups when compared to control fish, suggesting white cells migration to the tissues where antigen presentation is ongoing. Fish that received FIA-adjuvanted vaccine exhibited persistence of adjuvant deposits on intraperitoneal surfaces for at least 4 wpv that may be related to its superior performance compared to aluminum hydroxide adjuvanted vaccine, which did not evidence any type of deposit at any sampling times. The results observed in this study demonstrate that hydrogen peroxide-inactivated vaccine administered with either aluminum hydroxide or FIA induce optimal levels of protection, with a superior performance for FIA vaccine, which could be a good alternative to conventional formaldehyde-inactivated vaccines against S. agalactiae, due to its shorter manufacture time, and less toxicity.

Effect of Sulfated Polysaccharides from Marine Hydrobionts on Humoral Immune Response to Ovalbumin in Mice.

Adjuvant activity of fucoidans in experimental vaccine compositions with ovalbumin was studied on a mouse model. Compositions with sulfated polysaccharides from brown alga Fucus evanescens (native fucoidan in combination with polyphenols, and a product of fucoidan enzymatic hydrolysis) induced multiple productions of antigen-specific antibodies - total IgG, its isotypes IgG1 and, especially, IgG2a, in comparison with an individual ovalbumin. The adjuvant effect of native and structurally modified fucoidans is slightly inferior to that of the traditional licensed aluminum hydroxide adjuvant. The results indicate the prospects of using sulfated polysaccharides from F. evanescens as adjuvants in vaccines.

Aluminum hydroxide and calcium phosphate adjuvants in adsorbed tetanus and diphtheria vaccines: Immunologic vs histopathologic effects

Abstract We aimed to study effects of aluminum hydroxide (AH) and calcium phosphate (CAP) adjuvants in potentiation of new tetanus and diphtheria vaccines that have been developed in our laboratory. AH gel or CAP nanoparticles were prepared in vaccine formulations in adsorbed tetanus or tetanus-diphtheria (Td) vaccines. Vaccine formulations were injected to 8-week old female Balb/c mice. Only phosphate buffered saline (PBS) was injected to control animals. Tissue samples, peripheral blood samples and spleen cells were collected from each mouse. Serum was separated by centrifugation of peripheral blood. Spleen cells were stained with anti-CD4-FITC, anti-CD8-PE, and anti-CD19-APC monoclonal antibodies. ELISA was performed to test presence of anti-tetanus or anti-diphtheria antibodies. We found that either a single dose or an additional booster doses did not change significantly the composition of lymphocyte distribution in AH and CAP adjuvant injected mice in comparison to the control animals. No significant difference was detected for CD4/CD8 ratio and for CD19-expressing cell number. However, presence of IgM and IgG antibodies that were specific for both tetanus and diphtheria toxins increased significantly following injection of vaccines. Granulomas and cyst formation after subcutaneous injections of CAP-containing vaccines at the site of injection were evaluated. Supported by Gazi University BAP, No: 64/2018-04.

Glycoengineered hepatitis B virus-like particles with enhanced immunogenicity

Virus-like particles (VLP) represent biological platforms for the development of novel products such as vaccines and delivery platforms for foreign antigenic sequences. VLPs composed of the small surface antigen (HBsAgS) derived from the hepatitis B virus (HBV) are the immunogenic components of a licensed, preventative vaccine, which contains aluminum hydroxide as adjuvant. Herein, we report that glycoengineering of N-glycosylated HBsAgS to generate hyper-glycosylated VLPs display an enhanced immunogenicity relative to the wild type (WT) HBsAgS VLPs when expressed in FreeStyle HEK 293F cells. Comparative mass spectrometry-based N-glycan profiling, gel electrophoresis, and immunoassays demonstrated that WT and hyper-glycosylated HBsAgS VLPs contain the same type and distribution of N-glycan structures, but the latter shows a higher glycan abundance per protein mass. The antigenic integrity of the modified VLPs was also shown to be retained. To assess whether hyper-glycosylated VLPs induce an enhanced immune response in the presence of the adjuvant aluminum hydroxide, the anti-HBV surface antigen (anti-HBsAgS) antibody response was monitored in BALB/c mice, subcutaneously injected with different VLP derivatives. In the absence and presence of adjuvant, hyper-glycosylated VLPs showed an enhanced immunogenicity compared to WT VLPs. The ability of hyper-glycosylated VLPs to promote potent anti-HBsAgS immune responses compared to VLPs with a native N-glycan level as well as non-glycosylated, yeast-derived HBsAgS VLPs opens exciting avenues for generating more efficacious VLP-based vaccines against hepatitis B and improved HBsAgS VLP carrier platforms using glycoengineering.

Animals and Food of Animal Origin as a Potential Source of Salmonellosis: A Review of the Epidemiology, Laboratory Diagnosis, Economic Impact and Public Health Significance

Salmonellosis is an infectious disease of humans and animals caused frequently by two species of Salmonella (Salmonella enterica, and Salmonella bongori). Although primarily an intestinal bacterium, Salmonellae are widespread in the environment and are commonly found in farm effluents, human sewage and in any material that is subjected to fecal contamination. Salmonella cause diarrheal and systemic infections in humans. The infection most commonly results due to the consumption of food originating from animals and the environment. Studies have attributed that the subclinical infection in farm animals may lead to the contamination of meat, eggs, and milk or cause secondary contamination of fruits and vegetables that have been fertilized or irrigated with water containing fecal wastes. Salmonellosis causes significant economic loss in the management of farm animals. This can be attributed to the cost associated with the diagnosis and to treat the disease, the cost of cleaning and disinfection, and the cost of control and prevention. Moreover, emerging antimicrobial resistance can increase morbidity, mortality, and costs associated with disease management. Salmonellosis has both the social and economic consequences that require strong scientific and public health efforts to improve the situation. Because of the financial constraints, serological tests are conducted on a statistically representative sample of the population where the results are not always indicative of active infection in the herd. Enzyme-linked immunosorbent assays are available for some serovars of Salmonella and may be used for serological diagnosis and surveillance, especially in poultry and pigs. Vaccination, herd immunity, and antigenic cross-reactivity may compromise the diagnostic value of serological tests. Many inactivated vaccines are used against salmonellosis and some live vaccines are available commercially. Owing to the low efficacy of inactivated vaccines, oil or aluminum hydroxide adjuvants are used to improve their immunogenic properties. There is no vaccine to prevent salmonellosis in adults, whereas, a vaccine against Salmonella typhi has been developed, which is in use especially in children, but is only 60% effective. Prevention strategies include maintenance of sanitary/hygienic conditions in food processing plants, avoidance of cross-contamination of food, proper refrigeration of food, the supply of Salmonella free feed to animals, a strict inspection of meat originating from animals, detection and exclusion of carriers from food handling, and personal hygiene. Awareness should be created among the public about the risks associated with the consumption of raw meat, unpasteurized milk, smoked fish, un-cleaned vegetables, and contaminated water. This review attempts to highlight the role of farm animals in the transmission of salmonellosis, its epidemiology, laboratory diagnosis, economic impact, and public health significance.

Genetic Inhibition of Nfatc2 Attenuates Asparaginase Hypersensitivity in Mice

IntroductionThe development of a T cell‐dependent antibody response to asparaginase (ASNase) is the most common adverse effect of treatment with this chemotherapeutic agent for pediatric acute lymphoblastic leukemia (ALL). Anti‐ASNase antibodies decreases ASNase levels and drug efficacy and can mediate anaphylaxis. Transcription factors of the nuclear factor of activated T cells (NFAT) family play a critical role in Th cell activation, differentiation, and effector function. Here we show that a member of this family, Nfatc2 (NFAT1), upregulates Th2 responses, with Nfatc2‐deficient ASNase‐immunized mice being completely protected from anaphylaxis. Consistent with this, our clinical data demonstrate increased risk of ASNase hypersensitivity in pediatric ALL patients who express the NFATC2 rs6021191 intronic variant, which increases Nfatc2 expression, whereas the risk of ASNase hypersensitivity is decreased in ALL Down syndrome patients, who overexpress NFAT pathway inhibitors.HypothesisNfatc2 deficiency protects mice against ASNase‐induced hypersensitivity by suppressing type 2 immunity.MethodsNfatc2‐deficient mice and WT littermates were immunized with native E. coli ASNase using aluminum hydroxide adjuvant, after which immune cell phenotype and levels of basophil activation, cytokines, and ASNase‐specific antibody were determined. Hypersensitivity reactions to ASNase were assessed by detecting hypothermia with rectal thermometry. β‐hexosaminidase release was used for in vitro analysis of the degranulation of peritoneal mast cells (PMCs) obtained from naïve and ASNase‐immunized mice, while passive cutaneous anaphylaxis, passive systemic anaphylaxis, and active systemic anaphylaxis models were used for in vivo determinations.ResultsNfatc2‐deficient mice were protected against ASNase hypersensitivity reactions. Naïve Nfatc2‐deficient mice had fewer CD4+IL‐4+ cells and lower IL‐4 and IL‐13 levels than wild‐type mice. ASNase‐immunized Nfatc2‐deficient mice had increased levels of Treg cells and the regulatory cytokines, IL‐10 and TGF‐β1, along with decreased plasma IgG and IgE anti‐ASNase and total IgE levels. Consistent with this, basophils/peritoneal mast cells from Nfatc2‐deficient mice had decreased FcɛRI expression and IgE‐mediated activation.ConclusionNfatc2 deficiency decreases ASNase hypersensitivity by increasing regulatory responses and attenuating type 2 immune responses to ASNase immunization. Nfatc2 may be a promising target for the prevention of ASNase‐induced hypersensitivity.Support or Funding InformationUniversity of Pittsburgh School of Pharmacy & NIH Grants RO1 CA216815

Protection of outbred mice against a vaginal challenge by a Chlamydia trachomatis serovar E recombinant major outer membrane protein vaccine is dependent on phosphate substitution in the adjuvant

ABSTRACT Chlamydia trachomatis is the most common bacterial sexually-transmitted pathogen for which there is no vaccine. We previously demonstrated that the degree of phosphate substitution in an aluminum hydroxide adjuvant in a TLR-4-based C. trachomatis serovar E (Ser E) recombinant major outer membrane protein (rMOMP) formulation had an impact on the induced antibody titers and IFN-γ levels. Here, we have extended these observations using outbreed CD-1 mice immunized with C. trachomatis Ser E rMOMP formulations to evaluate the impact on bacterial challenge. The results confirmed that the rMOMP vaccine containing the adjuvant with the highest phosphate substitution induced the highest neutralizing antibody titers while the formulation with the lowest phosphate substitution induced the highest IFN-γ production. The most robust protection was observed in mice vaccinated with the formulation containing the adjuvant with the lowest phosphate substitution, as shown by the number of mice with positive vaginal cultures, number of positive cultures and number of C. trachomatis inclusion forming units recovered. This is the first report showing that vaccination of an outbred strain of mice with rMOMP induces protection against a vaginal challenge with C. trachomatis.

Adsorption onto aluminum hydroxide adjuvant protects antigens from degradation

Aluminum based adjuvants are widely used in commercial vaccines, since they are known to be safe and effective with a variety of antigens. The effect of antigen adsorption onto Aluminum Hydroxide is a complex area, since several mechanisms are involved simultaneously, whose impact is both antigen and formulation conditions dependent. Moreover, the mode of action of Aluminum Hydroxide is itself complex, with many mechanisms operating simultaneously. Within the literature there are contrasting theories regarding the effect of adsorption on antigen integrity and stability, with reports of antigen being stabilized by adsorption onto Aluminum Hydroxide, but also with contrary reports of antigen being destabilized. With the aim to understand the impact of adsorption on three recombinant proteins which, following in vivo immunization, are able to induce functional bactericidal antibodies against Neisseria meningitidis type B, we used a range of physico-chemical tools, such as DSC and UPLC, along with in vitro binding of antibodies that recognize structural elements of the proteins, and supported the in vitro data with in vivo evaluation in mice studies. We showed that, following exposure to accelerated degradation conditions involving heat, the recombinant proteins, although robust, were stabilized by adsorption onto Aluminum Hydroxide and retain their structural integrity unlike the not adsorbed proteins. The measure of the Melting Temperature was a useful tool to compare the behavior of proteins adsorbed and not adsorbed on Aluminum Hydroxide and to predict protein stability.

Hamster neogenin, a host-cell protein contained in a respiratory syncytial virus candidate vaccine, induces antibody responses in rabbits but not in clinical trial participants

ABSTRACT A recombinant respiratory syncytial virus (RSV) fusion glycoprotein candidate vaccine (RSV-PreF) manufactured in Chinese hamster ovary cells was developed for immunization of pregnant women, to protect newborns against RSV disease through trans-placental antibody transfer. Traces of a host-cell protein, hamster neogenin (haNEO1), were identified in purified RSV-PreF antigen material. Given the high amino-acid sequence homology between haNEO1 and human neogenin (huNEO1), there was a risk that potential vaccine-induced anti-neogenin immunity could affect huNEO1 function in mother or fetus. Anti-huNEO1 IgGs were measured by enzyme-linked immunosorbent assay in sera from rabbits and trial participants (Phase 1 and 2 trials enrolling 128 men and 500 non-pregnant women, respectively; NCT01905215/NCT02360475) collected after immunization with RSV-PreF formulations containing different antigen doses with/without aluminum-hydroxide adjuvant. In rabbits, four injections administered at 14-day intervals induced huNEO1-specific IgG responses in an antigen-dose- and adjuvant-dependent manner, which plateaued in the highest-dose groups after three injections. In humans, no vaccination-induced anti-huNEO1 IgG responses were detected upon a single immunization, as the values in vaccine and control groups fluctuated around pre-vaccination levels up to 90/360 days post-vaccination. A minority of participants had anti-huNEO1 levels ≥ assay cutoff before vaccination, which did not increase post-vaccination. Thus, despite detecting vaccine-induced huNEO1-specific responses in rabbits, we found no evidence that the candidate vaccine had induced anti-huNEO1 immunity in human adults. The antigen purification process was nevertheless optimized, and haNEO1-reduced vaccines were used in a subsequent Phase 2 trial enrolling 400 non-pregnant women (NCT02956837), in which again no vaccine-induced anti-huNEO1 responses were detected.