Neospora caninum antigens displaying virus-like particles as a bivalent vaccine candidate against neosporosis

Neospora caninum is a causative and transmissible agent of dog and bovine neosporosis. The resulting reproductive failures in infected cattle lead to significant economic losses worldwide. However, there is no satisfactory treatment or vaccine currently available to combat this pathogen. Thus, the development of appropriate vaccines to manage its infection and transmission is urgently needed. In this study, we expressed Rous sarcoma virus-like particles (RSV-LP) that displayed dual N. caninum antigens in silkworms. The antigen candidates are modified by adding a transmembrane domain of GP64 protein from Bombyx mori nucleopolyhedrovirus (BmNPV) to the C-terminus of surface antigen 1 (NcSAG1) and SAG1-related sequence 2 (NcSRS2). The NcSRS2 alone or the NcSAG1/NcSRS2 bivalent form displaying RSV-LPs were purified using sucrose density gradient centrifugation. These purified VLPs were then used for immunizations in gerbils, Meriones unguiculatus, to evaluate the anti-N. caninum effects in vivo. The results demonstrated that antigens displaying RSV-LPs in immunized gerbils produced the antigen-specific antibody, leading to a relatively lower parasite load after infections of N. caninum. To the best of our knowledge, this is the first study to present an RSV-LP vaccine displaying bivalent antigens from neosporosis. Taken together, our strategy suggests that silkworm-expressed virus-like particles (VLPs) are promising bivalent vaccine candidates against N. caninum infections.     

Pre-clinical safety and toxicology profile of a candidate vaccine to treat oxycodone use disorder

Opioid use disorders (OUD) and overdose represent a public health threat, resulting in thousands of deaths annually worldwide. Vaccines offer a promising treatment for OUD and potentially the prevention of fatal overdoses. The Oxy(Gly)₄-sKLH Conjugate Vaccine, Adsorbed (Oxy(Gly)₄-sKLH) has shown promising pre-clinical efficacy at reducing the behavioral and pharmacological effects of oxycodone. To support its clinical evaluation, a GLP toxicology study was performed to address the safety of Oxy(Gly)₄-sKLH. Sprague Dawley rats were vaccinated with either aluminum adjuvant (alum) or vaccine adsorbed on alum. Low and high doses of Oxy(Gly)₄-sKLH, equivalent to a 1X or 47X human dose, respectively, were administered every two weeks for a total of four vaccinations. Both vaccine doses induced high antibody titers. Vaccine-related toxicity was assessed postmortem in one experimental group after receiving the fourth immunization of the vaccine’s high dose. For the remaining experimental groups, rats were challenged with 1.5 mg/kg/day s.c. oxycodone for 7 days after the fourth vaccination to assess whether concurrent exposure to oxycodone in vaccinated animals resulted in toxicity. All rats, except a subset of the aluminum control and the high dose vaccine groups, were sacrificed following oxycodone exposure. These subsets were allowed a four weeks recovery period prior to euthanasia. In this study, no Oxy(Gly)₄-sKLH-related hematology, clinical chemistry, urinalysis, body weight, organ weight, or anatomic pathology toxicological findings were observed. These results demonstrate that the Oxy(Gly)₄-sKLH vaccine is well tolerated, is immunogenic even at low doses, and does not produce undesired side effects in rats.     

Evaluation of a downstream process for the recovery and concentration of a Cell-Culture-Derived rVSV-Spike COVID-19 vaccine candidate

rVSV-Spike (rVSV-S) is a recombinant viral vaccine candidate under development to control the COVID-19 pandemic and is currently in phase II clinical trials. rVSV-S induces neutralizing antibodies and protects against SARS-CoV-2 infection in animal models. Bringing rVSV-S to clinical trials required the development of a scalable downstream process for the production of rVSV-S that can meet regulatory guidelines. The objective of this study was the development of the first downstream unit operations for cell-culture-derived rVSV-S, namely, the removal of nucleic acid contamination, the clarification and concentration of viral harvested supernatant, and buffer exchange. Retaining the infectivity of the rVSV-S during the downstream process was challenged by the shear sensitivity of the enveloped rVSV-S and its membrane protruding spike protein. Through a series of screening experiments, we evaluated and established the required endonuclease treatment conditions, filter train composition, and hollow fiber-tangential flow filtration parameters to remove large particles, reduce the load of impurities, and concentrate and exchange the buffer while retaining rVSV-S infectivity. The combined effect of the first unit operations on viral recovery and the removal of critical impurities was examined during scale-up experiments. Overall, approximately 40% of viral recovery was obtained and the regulatory requirements of less than 10 ng host cell DNA per dose were met. However, while 86–97% of the host cell proteins were removed, the regulatory acceptable HCP levels were not achieved, requiring subsequent purification and polishing steps. The results we obtained during the scale-up experiments were similar to those obtained during the screening experiments, indicating the scalability of the process. The findings of this study set the foundation for the development of a complete downstream manufacturing process, requiring subsequent purification and polishing unit operations for clinical preparations of rVSV-S.     

Protection of White Leghorn chickens by recombinant fowlpox vector vaccine with an updated H5 insert against Mexican H5N2 avian influenza viruses

Despite decades of vaccination, surveillance, and biosecurity measures, H5N2 low pathogenicity avian influenza (LPAI) virus infections continue in Mexico and neighboring countries. One explanation for tenacity of H5N2 LPAI in Mexico is the antigenic divergence of circulating field viruses compared to licensed vaccines due to antigenic drift. Our phylogenetic analysis indicates that the H5N2 LPAI viruses circulating in Mexico and neighboring countries since 1994 have undergone antigenic drift away from vaccine seed strains. Here we evaluated the efficacy of a new recombinant fowlpox virus vector containing an updated H5 insert (rFPV-H5/2016), more relevant to the current strains circulating in Mexico. We tested the vaccine efficacy against a closely related subcluster 4 Mexican H5N2 LPAI (2010 H5/LP) virus and the historic H5N2 HPAI (1995 H5/HP) virus in White Leghorn chickens. The rFPV-H5/2016 vaccine provided hemagglutinin inhibition (HI) titers pre-challenge against viral antigens from both challenge viruses in almost 100% of the immunized birds, with no differences in number of birds seroconverting or HI titers among all tested doses (1.5, 2.0, and 3.1 log₁₀ mean tissue culture infectious doses/bird). The vaccine conferred 100% clinical protection and a significant decrease in oral and cloacal virus shedding from 1995 H5/HP virus challenged birds when compared to the sham controls at all tested doses. Virus shedding titers from vaccinated 2010 H5/LP virus challenged birds significantly decreased compared to sham birds especially at earlier time points. Our results confirm the efficacy of the new rFPV-H5/2016 against antigenic drift of LPAI virus in Mexico and suggest that this vaccine would be a good candidate, likely as a primer in a prime-boost vaccination program.     

The adjuvanted recombinant zoster vaccine co-administered with a tetanus,diphtheria and pertussis vaccine in adults aged ≥50 years: A randomized trial

BackgroundThis study evaluated immunogenicity and safety of the adjuvanted recombinant zoster vaccine (RZV) and the reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine (Tdap) when co-administered in adults aged ≥50 years.MethodsIn this open label, multi-center study (NCT02052596), participants were randomized 1:1 to the Co-Administration group (RZV dose 1 and Tdap at Day 0 [D0], RZV dose 2 at Month 2 [M2]) or Control group (Tdap at D0, RZV dose 1 at M2, RZV dose 2 at M4). Co-primary objectives were evaluation of the vaccine response rate (VRR) to RZV in the Co-Administration group, and demonstration of non-inferiority of the humoral responses to RZV and Tdap in the Co-Administration compared to Control group. Reactogenicity and safety of RZV and Tdap were also assessed.ResultsVRR to RZV was 97.8% in the Co-Administration group. The non-inferiority criterion was met for the humoral response to RZV and for 4 Tdap antigens, but was not met for the Tdap antigen pertactin. Occurrences of solicited, unsolicited and serious adverse events, and potential immune-mediated diseases were similar between groups.ConclusionsCo-administration of RZV and Tdap did not interfere with the humoral immune response to RZV or 4 of the 5 Tdap antigens. No safety concerns were identified.     

A novel lamprey antibody sequence to multimerize and increase the immunogenicity of recombinant viral and bacterial vaccine antigens

Hemagglutinin, the major surface protein of influenza viruses, was recombinantly expressed in eukaryotic cells as a monomer instead of its native trimer, and was only immunogenic when administered with an adjuvant [Pion et al. 2014]. In order to multimerize this antigen to increase its immunogenicity, a cysteine-rich peptide sequence found at the extreme C-terminus of lamprey variable lymphocyte receptor (VLR)-B antibodies was fused to various recombinant hemagglutinin (rHA) proteins from A and B influenza virus strains. The rHA-Lamp fusion (rHA fused to the lamprey sequence) protein was expressed in Leishmania tarentolae and Chinese hamster ovary (CHO) cells and shown to produce several multimeric forms. The multimers produced were very stable and more immunogenic in mice than monomeric rHA. The lamprey VLR-B sequence was also used to multimerize the neuraminidase (NA) of influenza viruses expressed in CHO cells. For some viral strains, the NA was expressed as a tetramer like the native viral NA form. In addition, the lamprey VLR-B sequence was fused with two surface antigens of Shigella flexneri 2a, the invasion plasmid antigen D and a double mutated soluble form of the membrane expression of the invasion plasmid antigen H namely MxiH. The fusion proteins were expressed in Escherichia coli to produce the respective multimer protein forms. The resulting proteins had similar multimeric forms as rHA-Lamp protein and were more immunogenic in mice than the monomer forms. In conclusion, the VLR-B sequence can be used to increase the immunogenicity of recombinant viral and bacterial antigens, thus negating the need for adjuvants.     

Effect of immune regulatory pathways after immunization with GMZ2 malaria vaccine candidate in healthy lifelong malaria-exposed adults

BackgroundDespite appreciable immunogenicity in malaria-naive populations, many candidate malaria vaccines are considerably less immunogenic in malaria-exposed populations. This could reflect induction of immune regulatory mechanisms involving Human Leukocyte Antigen G (HLA-G), regulatory T (Treg), and regulatory B (Breg) cells. Here, we addressed the question whether there is correlation between these immune regulatory pathways and both plasmablast frequencies and vaccine-specific IgG concentrations.MethodsFifty Gabonese adults with lifelong exposure to Plasmodium spp were randomized to receive three doses of either 30 µg or 100 µg GMZ2-CAF01, or 100 µg GMZ2-alum, or control vaccine (rabies vaccine) at 4-week intervals. Only plasma and peripheral blood mononuclear cells isolated from blood samples collected before (D0) and 28 days after the third vaccination (D84) of 35 participants were used to measure sHLA-G levels and anti-GMZ2 IgG concentrations, and to quantify Treg, Breg and plasmablast cells. Vaccine efficacy was assessed using controlled human malaria infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites (PfSPZ Challenge).ResultsThe sHLA-G concentration increased from D0 to D84 in all GMZ2 vaccinated participants and in the control group, whereas Treg frequencies increased only in those receiving 30 µg or 100 µg GMZ2-CAF01. The sHLA-G level on D84 was associated with a decrease of the anti-GMZ2 IgG concentration, whereas Treg frequencies on D0 or on D84, and Breg frequency on D84 were associated with lower plasmablast frequencies. Importantly, having a D84:D0 ratio of sHLA-G above the median was associated with an increased risk of P. falciparum infection after sporozoites injection.ConclusionRegulatory immune responses are induced following immunization. Stronger sHLA-G and Treg immune responses may suppress vaccine induced immune responses, and the magnitude of the sHLA-G response increased the risk of Plasmodium falciparum infection after CHMI. These findings could have implications for the design and testing of malaria vaccine candidates in semi-immune individuals.     

Effectiveness of recombinant zoster vaccine (RZV) in patients with inflammatory bowel disease

Background and AimsPatients with Inflammatory bowel disease (IBD) are at an increased risk of developing herpes zoster (HZ). The effectiveness of the recombinant zoster vaccine (RZV) in patients with IBD is unknown.MethodsIn this retrospective cohort study using Explorys (October 2017–April 2020; IBM Corporation, Somers, NY, USA), the effectiveness of RZV for the prevention of HZ in patients with IBD ≥ 50 years was compared to general population aged ≥ 50 years. Rates of de-novo HZ were compared between patients with IBD and the general population and stratified by number of RZV doses received. Results are presented as odds ratios (OR) with 95% confidence intervals (CI).ResultsThe overall proportion of IBD patients ≥ 50 years who received HZ vaccination with the live zoster vaccine (ZVL) or RZV was low (n = 11320, out of 112,200 IBD patients in the cohort). A total of 1670 patients received RZV. Receipt of the RZV resulted in a significantly lower rate of HZ in IBD patients (OR 0.36, 95% CI 0.23–0.56) compared to the general population (OR 0.74, 95% CI 0.59–0.92). However, despite vaccination, patients with IBD who received the RZV were still 3-times more likely to develop HZ during the study follow up period compared to the general population receiving the RZV (OR 3.06, 95% CI 1.87–5.02) and unvaccinated IBD patients were 6-times more likely to develop HZ compared to general population (OR 6.21, 95% CI 6.02–6.41).ConclusionThe recombinant zoster vaccine is effective in reducing the risk of HZ in patients with IBD compared to the general population. During our follow up period, patients with IBD, however, still remain at an increased risk for HZ despite vaccination.     

RelCoVax®, a two antigen subunit protein vaccine candidate against SARS-CoV-2 induces strong immune responses in mice

The COVID-19 pandemic has spurred an unprecedented movement to develop safe and effective vaccines against the SARS-CoV-2 virus to immunize the global population. The first set of vaccine candidates that received emergency use authorization targeted the spike (S) glycoprotein of the SARS-CoV-2 virus that enables virus entry into cells via the receptor binding domain (RBD). Recently, multiple variants of SARS-CoV-2 have emerged with mutations in S protein and the ability to evade neutralizing antibodies in vaccinated individuals. We have developed a dual RBD and nucleocapsid (N) subunit protein vaccine candidate named RelCoVax® through heterologous expression in mammalian cells (RBD) and E. coli (N). The RelCoVax® formulation containing a combination of aluminum hydroxide (alum) and a synthetic CpG oligonucleotide as adjuvants elicited high antibody titers against RBD and N proteins in mice after a prime and boost dose regimen administered 2 weeks apart. The vaccine also stimulated cellular immune responses with a potential Th1 bias as evidenced by increased IFN-γ release by splenocytes from immunized mice upon antigen exposure particularly N protein. Finally, the serum of mice immunized with RelCoVax® demonstrated the ability to neutralize two different SARS-CoV-2 viral strains in vitro including the Delta strain that has become dominant in many regions of the world and can evade vaccine induced neutralizing antibodies. These results warrant further evaluation of RelCoVax® through advanced studies and contribute towards enhancing our understanding of multicomponent subunit vaccine candidates against SARS-CoV-2.     

Cellular and humoral immunity to Ebola Zaire glycoprotein and viral vector proteins following immunization with recombinant vesicular stomatitis virus-based Ebola vaccine (rVSVΔG-ZEBOV-GP)

While effective at preventing Zaire ebolavirus (ZEBOV) disease, cellular immunity to ZEBOV and vector-directed immunity elicited by the recombinant vesicular stomatitis virus expressing ZEBOV glycoprotein (rVSVΔG-ZEBOV-GP) vaccine remain poorly understood. Sera and peripheral blood mononuclear cells were collected from 32 participants enrolled in a prospective multicenter study [ClinicalTrials.gov NCT02788227] before vaccination and up to six months post-vaccination. IgM and IgG antibodies, IgG-producing memory B cells (MBCs), and T cell reactivity to ZEBOV glycoprotein (ZEBOV-GP), vesicular stomatitis virus-Indiana strain (VSV-I) matrix (M) protein, and VSV-I nucleoprotein (NP) were measured using ELISA, ELISpot, and flow cytometry, respectively. 11/32 (34.4%) participants previously received a different investigational ZEBOV vaccine prior to enrollment and 21/32 (65.6%) participants were ZEBOV vaccine naïve. Both ZEBOV vaccine naïve and experienced participants had increased ZEBOV-GP IgG optical densities (ODs) post-rVSVΔG-ZEBOV-GP vaccination while only ZEBOV vaccine naïve participants had increased ZEBOV-GP IgM ODs. Transient IgM and IgG antibody responses to VSV-I M protein and NP were observed in a minority of participants. All participants had detectable ZEBOV-GP specific IgG-producing MBCs by 6 months post-vaccination while no changes were observed in the median IgG-producing MBCs to VSV-I proteins. T cell responses to ZEBOV-GP differed between ZEBOV vaccine experienced and ZEBOV vaccine naïve participants. T cell responses to both VSV-I M protein and VSV-I NP were observed, but were of a low magnitude. The rVSVΔG-ZEBOV-GP vaccine elicits robust humoral and memory B cell responses to ZEBOV glycoprotein in both ZEBOV vaccine naïve and experienced individuals and can generate vector-directed T cell immunity. Further research is needed to understand the significance of pre-existing vector and target antigen immunity on responses to booster doses of rVSVΔG-ZEBOV-GP and other rVSV-vectored vaccines.     

A phase 1 antigen dose escalation trial to evaluate safety,tolerability and immunogenicity of the leprosy vaccine candidate LepVax (LEP-F1 + GLA–SE) in healthy adults

Healthy United States-based adult volunteers with no history of travel to leprosy-endemic countries were enrolled for the first-in-human evaluation of LepVax (LEP-F1 + GLA-SE). In total 24 volunteers participated in an open-label clinical trial, with 21 receiving three injections of LepVax consisting of either 2 µg or 10 µg recombinant polyprotein LEP-F1 mixed with 5 µg of the GLA-SE adjuvant formulation. LepVax doses were provided by intramuscular injection on Days 0, 28, and 56, and safety was evaluated for one year following the final injection. LepVax was safe and well tolerated at both antigen doses. Immunological analyses indicated that similar LEP-F1-specific antibody and Th1 cytokine secretion (IFN-γ, IL-2, TNF) were induced by each of the antigen doses evaluated within LepVax. This clinical trial of the first defined vaccine candidate for leprosy demonstrates that LepVax is safe and immunogenic in healthy subjects and supports its advancement to testing in leprosy-endemic regions.     

Liposome engraftment and antigen combination potentiate the immune response towards conserved epitopes of the malaria vaccine candidate MSP2

Merozoite surface protein 2 (MSP2) is a highly abundant, GPI-anchored surface antigen on merozoites of the malaria parasite Plasmodium falciparum. It consists of highly conserved N- and C-terminal domains, and a central polymorphic region that allows all MSP2 alleles to be categorized into the 3D7 or FC27 family. Previously it has been shown that epitope accessibility differs between lipid-bound and lipid-free MSP2, suggesting that lipid interactions modulate the conformation and antigenicity in a way that may better mimic native MSP2 on the merozoite surface. Therefore, we have immunised mice with MSP2 engrafted onto liposomes using a C-terminal tether that mimics the native GPI anchor. To improve the immunogenicity of the formulated antigen, liposomes were supplemented with Pathogen Associated Molecular Pattern molecules, specifically agonists of the Toll-like receptor 4 (TLR4) or TLR2. Induced antibodies were directed mostly towards conserved epitopes, predominantly in the conserved C-terminal region of MSP2. We also found that immunisation with a combination of 3D7 and FC27 MSP2 enhanced antibody responses to conserved epitopes, and that the overall responses of mice immunised with MSP2-engrafted liposomes were comparable in magnitude to those of mice immunised with MSP2 formulated in Montanide ISA720. The antibodies elicited in mice by immunising with MSP2-engrafted liposomes recognised the native form of parasite MSP2 on western blots and were found to be cross-reactive with isolated 3D7 and FC27 merozoites when investigated by ELISA. The liposome-tethered MSP2 induced higher titres of complement-fixing antibodies to 3D7 and FC27 MSP2 than did MSP2 formulated in Montanide ISA720. Our results indicate that liposomal formulation represents a viable strategy for eliciting a strong immune response that favours conserved epitopes in MSP2 and thus a strain-transcendent immune response.     

Oral vaccine of recombinant Lactococcus lactis expressing the VP1 protein of duck hepatitis A virus type 3 induces mucosal and systemic immune responses

Duck hepatitis A virus (DHAV) is the major pathogen of duck viral hepatitis, which has caused great economic losses to duck breeding industry. As an effective delivery tool for protein antigens, Lactococcus lactis (L. lactis) has been successfully used to stimulate mucosal and systemic immune response. In this study, a recombinant L. lactis named NZ3900-VP1 was constructed, which could express VP1 protein of DHAV type 3 (DHAV-3) by using a nisin-controlled expression (NICE) system. The animal experiment in both mice and ducklings were performed to detect the immune response and protection effect of oral vaccination by the recombinant L. lactis. The results showed that oral vaccination with L. lactis NZ3900-VP1 significantly induced specific anti-VP1 IgG antibodies and mucosal secretory immunoglobulin A (sIgA) of DHAV-3 in mice and ducklings, and cytokines including interleukin-2 (IL-2), interferon gamma (IFN-γ), interleukin-10 (IL-10) and interleukin-4 (IL-4). Notably, the ducklings vaccinated with L. lactis NZ3900-VP1 were effectively protected when facing natural infestation of DHAV-3, which indicated that the recombinant L. lactis could serve as an effective vaccine to prevent DHAV-3 infection in ducklings.     

A prime-boost concept using a T-cell epitope-driven DNA vaccine followed by a whole virus vaccine effectively protected pigs in the pandemic H1N1 pig challenge model

Influenza A virus (IAV) vaccines in pigs generally provide homosubtypic protection but fail to prevent heterologous infections. In this pilot study, the efficacy of an intradermal pDNA vaccine composed of conserved SLA class I and class II T cell epitopes (EPITOPE) against a homosubtypic challenge was compared to an intramuscular commercial inactivated whole virus vaccine (INACT) and a heterologous prime boost approach using both vaccines. Thirty-nine IAV-free, 3-week-old pigs were randomly assigned to one of five groups including NEG-CONTROL (unvaccinated, sham-challenged), INACT-INACT-IAV (vaccinated with FluSure XP® at 4 and 7 weeks, pH1N1 challenged), EPITOPE-INACT-IAV (vaccinated with PigMatrix EDV at 4 and FluSure XP® at 7 weeks, pH1N1 challenged), EPITOPE-EPITOPE-IAV (vaccinated with PigMatrix EDV at 4 and 7 weeks, pH1N1 challenged), and a POS-CONTROL group (unvaccinated, pH1N1 challenged). The challenge was done at 9 weeks of age and pigs were necropsied at day post challenge (dpc) 5. At the time of challenge, all INACT-INACT-IAV pigs, and by dpc 5 all EPITOPE-INACT-IAV pigs were IAV seropositive. IFNγ secreting cells, recognizing vaccine epitope-specific peptides and pH1N1 challenge virus were highest in the EPITOPE-INACT-IAV pigs at challenge. Macroscopic lung lesion scores were reduced in all EPITOPE-INACT-IAV pigs while INACT-INACT-IAV pigs exhibited a bimodal distribution of low and high scores akin to naïve challenged animals. No IAV antigen in lung tissues was detected at necropsy in the EPITOPE-INACT-IAV group, which was similar to naïve unchallenged pigs and different from all other challenged groups. Results suggest that the heterologous prime boost approach using an epitope-driven DNA vaccine followed by an inactivated vaccine was effective against a homosubtypic challenge, and further exploration of this vaccine approach as a practical control measure against heterosubtypic IAV infections is warranted.     

Statin use and medically attended acute respiratory illness among influenza vaccine recipients

BackgroundPrevious studies have suggested that statins decrease influenza vaccine effectiveness and increase risk of medically attended acute respiratory illness (MAARI).ObjectivesTo examine the association of incident statin use and MAARI in a cohort of influenza vaccine recipients.MethodsThis retrospective cohort study evaluated influenza vaccine recipients within the Tricare population. The primary outcome compared MAARI incidence during the follow-up period in a propensity score-matched cohort of incident statin users and statin non-users. Secondary analysis included propensity score-adjusted comparisons between incident statin users and statin non-users in the entire cohort and prespecified sub-cohorts with and without comorbidities. The propensity score was derived from 72 variables encompassing demographics, medical history, comorbidities, medication use, and healthcare utilization.ResultsMAARI incidence in statin users was similar to non-users in the propensity score-matched cohort (odds ratio [OR] 0.92; 95% confidence interval [CI] 0.84–1.01). In contrast, statin users with lower comorbidity had lower OR for MAARI compared to non-users (Charlson Score zero cohort: 0.85 [CI 0.74–0.98]; No Diabetes cohort: 0.88 [CI 0.80–0.96]).ConclusionIncident statin use was not associated with increased MAARI incidence and may be associated with lower incidence of MAARI in those with less comorbidity. This study thus offers reassurance regarding the effectiveness of the influenza vaccine in statin users.     

Phosphorothioated antisense oligodeoxynucleotide suppressing interleukin-10 is a safe and potent vaccine adjuvant

While vaccination is highly effective for the prevention of many infectious diseases, the number of adjuvants licensed for human use is currently very limited. The aim of this study was to evaluate the safety, efficacy, and to clarify the mechanism of a phosphorothioated interleukin (IL)-10-targeted antisense oligonucleotide (ASO) as an immune adjuvant in intradermal vaccination. The cytotoxicity of IL-10 ASO and its ability to promote T cell proliferation were assessed by Cell Counting Kit-8 (CCK-8) assay. The contents of IL-6, IL-8, TNF-α, IL-1β, and IL-10 in inoculated local tissue and the antigen-specific antibody titers in mouse serum samples were determined by ELISA. The target cells of IL-10 ASO were observed using immunofluorescent staining. The results showed that the specific antibody titer of ovalbumin (OVA), a model antigen, was increased 100-fold upon addition of IL-10 ASO as an adjuvant compared to that of OVA alone. IL-10 ASO showed an immunopotentiation efficacy similar to that of Freund’s incomplete adjuvant, with no detectable cell or tissue toxicity. In vitro and in vivo experiments confirmed that IL-10 ASO enhances immune responses by temporarily suppressing IL-10 expression from local dendritic cells and consequently promoting T cell proliferation. In conclusion, IL-10 ASO significantly enhances immune responses against co-delivered vaccine antigens with high efficacy and low toxicity. It has the potential to be developed into a safe and efficient immune adjuvant.     

Heroin vaccine: Using titer,affinity, and antinociception as metrics when examining sex and strain differences

Anti-drug vaccines have potential as new interventions against substance use disorder (SUD). However, given the challenges seen with inter-individual variability in SUD vaccine trials to date, new interventions should ensure a robust immune response and safety profile among a diverse population. This requires accounting for sex and heritable genetic differences in response to both abused substances as well as the vaccination itself. To test response variability to our heroin-tetanus toxoid (Her-TT) immunoconjugate vaccine, we vaccinated male and female mice from several mouse strains including Swiss Webster (SW), BALB/c, and Jackson diversity mice (J:DO). Previous studies with vaccinated male SW mice demonstrated a rare hypersensitivity resulting in mice rapidly expiring with exposure to a low dose of heroin. Our results indicate that this response is limited to only male SW mice, and not to any other strain or female SW mice. Our data suggest that this hypersensitivity is not the result of an overactive cytokine or IgE response. Vaccination was similarly effective among the sexes for each strain and against repeated heroin challenge. Inbred BALB/c and J:DO mice were found to have the best vaccine response against heroin in antinociception behavioral assay. These results highlight the importance of incorporating both male and female subjects, along with different strains to mimic diverse human populations, as new SUD vaccines are being tested.     

Advanced oxidation technology for the development of a next-generation inactivated West Nile virus vaccine

West Nile virus (WNV) is the most frequent mosquito-borne disease reported in the continental United States and although an effective veterinary vaccine exists for horses, there is still no commercial vaccine approved for human use. We have previously tested a 3% hydrogen peroxide (H₂O₂)-based WNV inactivation approach termed, HydroVax, in Phase I clinical trials and the vaccine was found to be safe and modestly immunogenic. Here, we describe an advanced, next-generation oxidation approach (HydroVax-II) for the development of inactivated vaccines that utilizes reduced concentrations of H₂O₂ in combination with copper (cupric ions, Cu²⁺) complexed with the antiviral compound, methisazone (MZ). Further enhancement of this oxidative approach included the addition of a low percentage of formaldehyde, a cross-linking reagent with a different mechanism of action that, together with H₂O₂/Cu/MZ, provides a robust two-pronged approach to virus inactivation. Together, this new approach results in rapid virus inactivation while greatly improving the maintenance of WNV-specific neutralizing epitopes mapped across the three structural domains of the WNV envelope protein. In combination with more refined manufacturing techniques, this inactivation technology resulted in vaccine-mediated WNV-specific neutralizing antibody responses that were 130-fold higher than that observed using the first generation, H₂O₂-only vaccine approach and provided 100% protection against lethal WNV infection. This new approach to vaccine development represents an important area for future investigation with the potential not only for improving vaccines against WNV, but other clinically relevant viruses as well.