Journal Description

Vaccines — Open Access Journal

Vaccines (ISSN 2076-393X; CODEN: VBSABP) is an international peer-reviewed open access journal published quarterly online by MDPI. The American Society for Virology (ASV) is affiliated with Vaccines and their members receive a discount on the article processing charges.

Open Access—free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: Indexed in the Science Citation Index Expanded (SCIE) and BIOSIS Previews in Web of Science and in Scopus. Citations available in PubMed, full-text archived in PubMed Central.
CiteScore (2019 Scopus data): 4.5, which equals rank 92/283 (Q2) in the category 'Infectious Diseases', rank 116/200 (Q3) in 'Immunology' and rank 109/301 (Q2) in 'Pharmacology', among others.
Rapid Publication: manuscripts are peer-reviewed and a first decision provided to authors approximately 12.9 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the first half of 2020).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.

Impact Factor: 4.086 (2019)

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Latest Articles

Open AccessArticle

A Novel Rhoptry Protein as Candidate Vaccine against Eimeria tenella Infection

Xingju Song ,

Xu Yang ,

Taotao Zhang ,

Jing Liu and

Qun Liu

Vaccines 2020, 8(3), 452; https://doi.org/10.3390/vaccines8030452 (registering DOI) - 12 Aug 2020

Abstract

Eimeria tenella (E. tenella) is a highly pathogenic and prevalent species of Eimeria that infects chickens, and it causes a considerable disease burden worldwide. The secreted proteins and surface antigens of E. tenella at the sporozoite stage play an essential role in the host–parasite interaction, which involves attachment and invasion, and these interactions are considered vaccine candidates based on the strategy of cutting off the invasion pathway to interrupt infection. We selected two highly expressed surface antigens (SAGs; Et-SAG13 and Et-SAG) and two highly expressed secreted antigens (rhoptry kinases Eten5-A, Et-ROPK-Eten5-A and dense granule 12, Et-GRA12) at the sporozoite stage. Et-ROPK-Eten5-A and Et-GRA12 were two unexplored proteins. Et-ROPK-Eten5-A was an E. tenella-specific rhoptry (ROP) protein and distributed in the apical pole of sporozoites and merozoites. Et-GRA12 was scattered in granular form at the sporozoite stage. To evaluate the potential of rEt-ROPK-Eten5-A, rEt-GRA12, rEt-SAG13 and rEt-SAG proteins as a coccidiosis vaccine, the protective efficacy was examined based on survival rate, lesion score, body weight gain, relative body weight gain and oocyst output. The survival rate was significantly improved in rEt-ROPK-Eten5-A (100%) and rEt-GRA12 (100%) immune chickens compared to the challenged control group (40%). The average body weight gains of rEt-ROPK-Eten5-A, rEt-GRA12, rEt-SAG13 and rEt-SAG immunized chickens were significantly higher than those of unimmunized chickens. The mean lesion score and oocyst output of the rEt-ROPK-Eten5-A immunized chickens were significantly reduced compared to unimmunized challenged chickens. These results suggest that the rEt-ROPK-Eten5-A protein effectively triggered protection against E. tenella in chickens and provides a useful foundation for future work developing anticoccidial vaccines. Full article

(This article belongs to the Special Issue Poultry Vaccines)

Open AccessReview

Tick-Borne Encephalitis Virus: A Quest for Better Vaccines against a Virus on the Rise

Mareike Kubinski ,

Jana Beicht ,

Thomas Gerlach ,

Asisa Volz ,

Gerd Sutter and

Guus F. Rimmelzwaan

Vaccines 2020, 8(3), 451; https://doi.org/10.3390/vaccines8030451 (registering DOI) - 12 Aug 2020

Abstract

Tick-borne encephalitis virus (TBEV), a member of the family Flaviviridae, is one of the most important tick-transmitted viruses in Europe and Asia. Being a neurotropic virus, TBEV causes infection of the central nervous system, leading to various (permanent) neurological disorders summarized as tick-borne encephalitis (TBE). The incidence of TBE cases has increased due to the expansion of TBEV and its vectors. Since antiviral treatment is lacking, vaccination against TBEV is the most important protective measure. However, vaccination coverage is relatively low and immunogenicity of the currently available vaccines is limited, which may account for the vaccine failures that are observed. Understanding the TBEV-specific correlates of protection is of pivotal importance for developing novel and improved TBEV vaccines. For affording robust protection against infection and development of TBE, vaccines should induce both humoral and cellular immunity. In this review, the adaptive immunity induced upon TBEV infection and vaccination as well as novel approaches to produce improved TBEV vaccines are discussed. Full article

(This article belongs to the Special Issue Genomic Medicine and Advances in Vaccine Technology and Development in the Developing and Developed World)

Open AccessArticle

Assessing the Immune Response of Atlantic Salmon (Salmo salar) after the Oral Intake of Alginate-Encapsulated Piscirickettsia salmonis Antigens

Daniela Sotomayor-Gerding ,

José Miguel Troncoso ,

Alejandro Pino ,

Felipe Almendras and

Mónica Rubilar Diaz

Vaccines 2020, 8(3), 450; https://doi.org/10.3390/vaccines8030450 - 11 Aug 2020

Abstract

Salmon rickettsial septicaemia (SRS) is the infectious disease that produces the highest losses in the Chilean salmon industry. As a new strategy for the control of SRS outbreaks, in this study we evaluated the effect of alginate-encapsulated Piscirickettsia salmonis antigens (AEPSA) incorporated in the feed as an oral vaccine to induce the immune response in Atlantic salmon (Salmo salar). Fish were distributed into three vaccination groups (injectable, oral high dose, oral low dose). Feed intake and fish growth were recorded during the trial. The P. salmonis-specific IgM levels in blood plasma were measured by ELISA. Alginate microparticles containing the antigen were effectively incorporated in fish feed to produce the oral vaccine. Incorporation of AEPSA did not affect the palatability of the feed or the fish appetite. Furthermore, the oral vaccine did not have a negative effect on fish growth. Finally, the oral vaccine (high and low dose) produced an acquired immune response (IgM) similar to the injectable vaccine, generating a statistically significant increase in the IgM levels at 840-degree days for both experimental groups. These findings suggest that AEPSA incorporated in the feed can be an effective alternative to boost the immune response in Atlantic salmon (S. salar). Full article

(This article belongs to the Section Veterinary Vaccines)

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Open AccessArticle

Vaccine Efficacy on the Novel Reassortant H9N2 Virus in Indonesia

Ni Luh Putu Indi Dharmayanti ,

Risa Indriani and

Diana Nurjanah

Vaccines 2020, 8(3), 449; https://doi.org/10.3390/vaccines8030449 - 10 Aug 2020

Abstract

Vaccination is one of the leading methods of controlling the spread of the Avian Influenza (AI) viruses in Indonesia. The variety of circulating viruses and their ability to mutate must be followed by updating the vaccine master seed used in the field. In this study, we identified the reassortant H9N2 viruses in chicken farms that showed significant problems in decreased egg production with high mortality. The reassortant H9N2 viruses derived the PB2 gene from the H5N1 virus. The pathogenicity test results of the reassortant virus showed various clinical signs of illness, a high mortality rate (10%), and decreased egg production down to 63.12% at two weeks post-infection. In a vaccine efficacy test, the vaccinated groups showed minimally decreased egg production that started to increase to more than 80% at 4–7 weeks post-challenge. Our study showed that inactivated bivalent and monovalent reassortant H9N2 vaccines can induce antibody response, reducing the mortality and virus shedding caused by reassortant H9N2 virus infection. The reassortant H9N2 virus is a threat that requires vigilance in poultry farms and the industry. The vaccines used in this study can be one of the options for control or prevention measures on farms infected with the reassortant H9N2 viruses. Full article

(This article belongs to the Special Issue Poultry Vaccines)

Open AccessArticle

Immunogenicity and Protective Efficacy of Influenza A DNA Vaccines Encoding Artificial Antigens Based on Conservative Hemagglutinin Stem Region and M2 Protein in Mice

Sergei Bazhan ,

Denis Antonets ,

Ekaterina Starostina ,

Tatyana Ilyicheva ,

Olga Kaplina ,

Vasiliy Marchenko ,

Alexander Durymanov ,

Svetlana Oreshkova and

Larisa Karpenko

Vaccines 2020, 8(3), 448; https://doi.org/10.3390/vaccines8030448 - 09 Aug 2020

Abstract

Background: Development of a universal vaccine capable to induce antibody responses against a broad range of influenza virus strains attracts growing attention. Hemagglutinin stem and the exposed fragment of influenza virus M2 protein are promising targets for induction of cross-protective humoral and cell-mediated response, since they contain conservative epitopes capable to induce antibodies and cytotoxic T lymphocytes (CTLs) to a wide range of influenza virus subtypes. Methods: In this study, we generated DNA vaccine constructs encoding artificial antigens AgH1, AgH3, and AgM2 designed on the basis of conservative hemagglutinin stem fragments of two influenza A virus subtypes, H1N1 and H3N2, and conservative M2 protein, and evaluate their immunogenicity and protective efficacy. To obtain DNA vaccine constructs, genes encoding the designed antigens were cloned into a pcDNA3.1 vector. Expression of the target genes in 293T cells transfected with DNA vaccine constructs has been confirmed by synthesis of specific mRNA. Results: Immunization of BALB/c mice with DNA vaccines encoding these antigens was shown to evoke humoral and T-cell immune responses as well as a moderated statistically significant cross-protective effect against two heterologous viruses A/California/4/2009 (H1N1pdm09) and A/Aichi/2/68 (H3N2). Conclusions: The results demonstrate a potential approach to creating a universal influenza vaccine based on artificial antigens. Full article

(This article belongs to the Special Issue Influenza Virus and Vaccine Development)

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Open AccessReview

Immuno-Oncotherapeutic Approaches in Advanced Hepatocellular Carcinoma

Robin Park ,

Fariha Eshrat ,

Mohammed Al-Jumayli ,

Azhar Saeed and

Anwaar Saeed

Vaccines 2020, 8(3), 447; https://doi.org/10.3390/vaccines8030447 - 08 Aug 2020

Abstract

Advanced hepatocellular carcinoma has limited treatment options, but there has been extensive growth recently with cabozantinib, regorafenib, lenvatinib, nivolumab, atezolizumab, and bevacizumab, which are some of the treatments that have received FDA approval just over the last three years. Because HCC tumor microenvironment is potentially immunogenic and typically characterized by inflammation, immunotherapy has been proposed as a potential novel therapeutic approach, which has prompted studies in advanced HCC patients investigating various immune-therapeutic strategies such as CAR-T cell therapy, checkpoint inhibitors, and onco-vaccines. The anti-PD-1 checkpoint inhibitors nivolumab and pembrolizumab have been FDA approved as a second line treatment in patients who progressed or are intolerant to Sorafenib. To build up on the success of PD-1 monotherapy, combinatorial regimens with PD-1/PD-L1 inhibitors plus VEGF targeted agents have shown positive results in various malignancies including HCC. The combination of atezolizumab plus bevacizumab is the new addition to the HCC treatment armamentarium following a pivotal study that demonstrated an improvement in OS over frontline sorafenib. Other novel immune-based approaches and oncolytic viruses are in the early phases of clinical evaluation. These innovative approaches enhance the intensity of cancer-directed immune responses and will potentially impact the outlook of this aggressive disease. Full article

(This article belongs to the Special Issue Cancer Vaccine)

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Open AccessArticle

Evaluating the Relative Vaccine Effectiveness of Adjuvanted Trivalent Influenza Vaccine Compared to High-Dose Trivalent and Other Egg-Based Influenza Vaccines among Older Adults in the US during the 2017–2018 Influenza Season

Stephen I. Pelton ,

Victoria Divino ,

Drishti Shah ,

Joaquin Mould-Quevedo ,

Mitch DeKoven ,

Girishanthy Krishnarajah and

Maarten J. Postma

Vaccines 2020, 8(3), 446; https://doi.org/10.3390/vaccines8030446 - 07 Aug 2020

Abstract

The influenza-related disease burden is highest among the elderly. We evaluated the relative vaccine effectiveness (rVE) of adjuvanted trivalent influenza vaccine (aTIV) compared to other egg-based influenza vaccines (high-dose trivalent (TIV-HD), quadrivalent (QIVe-SD), and standard-dose trivalent (TIVe-SD)) against influenza-related and cardio-respiratory events among subjects aged ≥65 years for the 2017–2018 influenza season. This retrospective cohort analysis used prescription claims, professional fee claims, and hospital charge master data. Influenza-related hospitalizations/ER visits and office visits and cardio-respiratory events were assessed post-vaccination. Inverse probability of treatment weighting (IPTW) and Poisson regression were used to evaluate the adjusted rVE of aTIV compared to other vaccines. In an economic analysis, annualized follow-up costs were compared between aTIV and TIV-HD. The study was composed of 234,313 aTIV, 1,269,855 TIV-HD, 212,287 QIVe-SD, and 106,491 TIVe-SD recipients. aTIV was more effective in reducing influenza-related office visits and other respiratory-related hospitalizations/ER visits compared to the other vaccines. For influenza-related hospitalizations/ER visits, aTIV was associated with a significantly higher rVE compared to QIVe-SD and TIVe-SD and was comparable to TIV-HD. aTIV was also associated with a significantly higher rVE compared to TIVe-SD against hospitalizations/ER visits related to pneumonia and asthma/COPD/bronchial events. aTIV and TIV-HD were associated with comparable annualized all-cause and influenza-related costs. Adjusted analyses demonstrated a significant benefit of aTIV against influenza- and respiratory-related events compared to the other egg-based vaccines. Full article

(This article belongs to the Section Influenza Virus Vaccines)

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Open AccessEditorial

Invited Editorial: Despite COVID-19, Influenza Must Not Be Relegated to “Only the Sniffles”

Graham Pawelec

Vaccines 2020, 8(3), 445; https://doi.org/10.3390/vaccines8030445 - 07 Aug 2020

Abstract

As the current COVID-19 pandemic continues to rage worldwide, it has emerged that the 2019–2020 influenza season has been milder and shorter than usual in the northern hemisphere, presumably due to enforced social distancing [...] Full article

Open AccessArticle

SARS-CoV-2 Consensus-Sequence and Matching Overlapping Peptides Design for COVID19 Immune Studies and Vaccine Development

Alex Olvera ,

Marc Noguera-Julian ,

Athina Kilpelainen ,

Luis Romero-Martín ,

Julia G. Prado and

Christian Brander

Vaccines 2020, 8(3), 444; https://doi.org/10.3390/vaccines8030444 - 06 Aug 2020

Abstract

Synthetic antigens based on consensus sequences that represent circulating viral isolates are sensitive, time saving and cost-effective tools for in vitro immune monitoring and to guide immunogen design. When based on a representative sequence database, such consensus sequences can effectively be used to test immune responses in exposed and infected individuals at the population level. To accelerate immune studies in SARS-CoV-2 infection, we here describe a SARS-CoV-2 2020 consensus sequence (CoV-2-cons) which is based on more than 1700 viral genome entries in NCBI and encompasses all described SARS-CoV-2 open reading frames (ORF), including recently described frame-shifted and length variant ORF. Based on these sequences, we created curated overlapping peptide (OLP) lists containing between 1500 to 3000 peptides of 15 and 18 amino acids in length, overlapping by 10 or 11 residues, as ideal tools for the assessment of SARS-CoV-2-specific T cell immunity. In addition, CoV-2-cons sequence entropy values are presented along with variant sequences to provide increased coverage of the most variable sections of the viral genome. The identification of conserved protein fragments across the coronavirus family and the corresponding OLP facilitate the identification of T cells potentially cross-reactive with related viruses. This new CoV-2-cons sequence, together with the peptides sets, should provide the basis for SARS-CoV-2 antigen synthesis to facilitate comparability between ex-vivo immune analyses and help to accelerate research on SARS-CoV-2 immunity and vaccine development. Full article

(This article belongs to the Section Vaccines against Infectious Diseases)

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Open AccessReview

Investigating Virological, Immunological, and Pathological Avenues to Identify Potential Targets for Developing COVID-19 Treatment and Prevention Strategies

Sheikh Abdul Rahman ,

Shereen Elshaer ,

Gaber EI-Saber Batiha and

Khalid Muhammad

Vaccines 2020, 8(3), 443; https://doi.org/10.3390/vaccines8030443 - 06 Aug 2020

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging coronavirus causing respiratory disease commonly known as COVID-19. This novel coronavirus transmits from human to human and has caused profound morbidity and mortality worldwide leading to the ongoing pandemic. Moreover, disease severity differs considerably from individual to individual. Investigating the virology of COVID-19 and immunological pathways underlying its clinical manifestations will enable the identification and design of effective vaccines and potential therapies. In this review, we explore COVID-19 virology, the contribution of the immune system (innate and adaptive) during infection and control of the virus. Finally, we highlight vaccine development and implications of immune system modulation for potential therapeutic interventions to design better therapeutic strategies to guide future cure. Full article

(This article belongs to the Special Issue B and T Cell-Mediated Immunity)

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Open AccessReview

Antiretroviral Therapy Interruption (ATI) in HIV-1 Infected Patients Participating in Therapeutic Vaccine Trials: Surrogate Markers of Virological Response

Lorna Leal ,

Csaba Fehér ,

Valèria Richart ,

Berta Torres and

Felipe García

Vaccines 2020, 8(3), 442; https://doi.org/10.3390/vaccines8030442 - 05 Aug 2020

Abstract

A functional Human immunodeficiency Virus (HIV) cure has been proposed as an alternative to antiretroviral treatment for life, and therapeutic vaccines represent one of the most promising approaches. The goal of therapeutic vaccination is to augment virus-specific immune responses that have an impact on HIV viral load dynamics. To date, the agreed feature to evaluate the effects of these therapeutic interventions is analytical antiretroviral treatment interruption (ATI), at least until we find a reliable biomarker that can predict viral control. Different host, immunologic, and virologic markers have been proposed as predictors of viral control during ATI after therapeutic interventions. This review describes the relevance of ATI and the different surrogate markers of virological control assessed in HIV therapeutic vaccine clinical trials. Full article

(This article belongs to the Special Issue Therapeutic Vaccination of HIV-infected Patients)

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Open AccessArticle

Novel Trivalent Vectored Vaccine for Control of Myxomatosis and Disease Caused by Classical and a New Genotype of Rabbit Haemorrhagic Disease Virus

Sylvia Reemers ,

Leon Peeters ,

Joyce van Schijndel ,

Beth Bruton ,

David Sutton ,

Leo van der Waart and

Saskia van de Zande

Vaccines 2020, 8(3), 441; https://doi.org/10.3390/vaccines8030441 - 05 Aug 2020

Abstract

Myxoma virus (MV) and rabbit haemorrhagic disease virus (RHDV) are the major causes of lethal viral diseases in the European rabbit. In 2010, a new RHDV genotype (RHDV2) emerged in the field that had limited cross-protection with the classical RHDV (RHDV1). For optimal protection of rabbits and preventing spread of disease, a vaccine providing protection against all three key viruses would be ideal. Therefore, a novel trivalent myxoma vectored RHDV vaccine (Nobivac Myxo-RHD PLUS) was developed similar to the existing bivalent myxoma vectored RHDV vaccine Nobivac Myxo-RHD. The new vaccine contains the Myxo-RHDV1 strain already included in Nobivac Myxo-RHD and a similarly produced Myxo-RHDV2 strain. This paper describes several key safety and efficacy studies conducted for European licensing purposes. Nobivac Myxo-RHD PLUS showed to be safe for use in rabbits from five weeks of age onwards, including pregnant rabbits, and did not spread from vaccinated rabbits to in-contact controls. Furthermore, protection to RHDV1 and RHDV2 was demonstrated by challenge, while the serological response to MV was similar to that after vaccination with Nobivac Myxo-RHD. Therefore, routine vaccination with Nobivac Myxo-RHD PLUS can prevent the kept rabbit population from these major viral diseases. Full article

Open AccessArticle

Optimized Hepatitis C Virus (HCV) E2 Glycoproteins and their Immunogenicity in Combination with MVA-HCV

María Q. Marín ,

Kwinten Sliepen ,

Juan García-Arriaza ,

Sylvie M. Koekkoek ,

Patricia Pérez ,

Carlos Óscar S. Sorzano ,

Carmen E. Gómez ,

Rogier W. Sanders and

Mariano Esteban

Vaccines 2020, 8(3), 440; https://doi.org/10.3390/vaccines8030440 - 05 Aug 2020

Abstract

Hepatitis C virus (HCV) represents a major global health challenge and an efficient vaccine is urgently needed. Many HCV vaccination strategies employ recombinant versions of the viral E2 glycoprotein. However, recombinant E2 readily forms disulfide-bonded aggregates that might not be optimally suited for vaccines. Therefore, we have designed an E2 protein in which we strategically changed eight cysteines to alanines (E2.C8A). E2.C8A formed predominantly monomers and virtually no aggregates. Furthermore, E2.C8A also interacted more efficiently with broadly neutralizing antibodies than conventional E2. We used mice to evaluate different prime/boost immunization strategies involving a modified vaccinia virus Ankara (MVA) expressing the nearly full-length genome of HCV (MVA-HCV) in combination with either the E2 aggregates or the E2.C8A monomers. The combined MVA-HCV/E2 aggregates prime/boost strategy markedly enhanced HCV-specific effector memory CD4⁺ T cell responses and antibody levels compared to MVA-HCV/MVA-HCV. Moreover, the aggregated form of E2 induced higher levels of anti-E2 antibodies in vaccinated mice than E2.C8A monomers. These antibodies were cross-reactive and mainly of the IgG1 isotype. Our findings revealed how two E2 viral proteins that differ in their capacity to form aggregates are able to enhance to different extent the HCV-specific cellular and humoral immune responses, either alone or in combination with MVA-HCV. These combined protocols of MVA-HCV/E2 could serve as a basis for the development of a more effective HCV vaccine. Full article

(This article belongs to the Section Hepatitis Virus Vaccines)

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Open AccessEditorial

Listeria monocytogenes as a Vector for Cancer Immunotherapy

Jorge H. Leitão

Vaccines 2020, 8(3), 439; https://doi.org/10.3390/vaccines8030439 - 05 Aug 2020

Abstract

Cancer is a wide group of diseases, which was responsible for 9.6 million deaths in 2018. Cancer immunotherapies have become a reality, with the first approval for sipuleucel-T for prostate cancer therapy occurring in 2010. Listeria monocytogenes is a Gram-positive bacterium, mostly known as a food-borne pathogen, capable of causing life-threatening and often fatal infections. However, since in the majority of cases the human immune system is able to mount potent innate and adaptive immune responses that control infections by Listeria monocytogenes, the microorganism has become an attractive vector for the development of cancer vaccines. The review by Flickinger Jr., Rodeck and Snook (Vaccines 2018, 6, 48) on the use of Listeria monocytogenes as a vector for cancer immunotherapy is described and commented here. Full article

Open AccessArticle

Distinct miRNA Profile of Cellular and Extracellular Vesicles Released from Chicken Tracheal Cells Following Avian Influenza Virus Infection

Kelsey O’Dowd ,

Mehdi Emam ,

Mohamed Reda El Khili ,

Amin Emad ,

Eveline M. Ibeagha-Awemu ,

Carl A. Gagnon and

Neda Barjesteh

Vaccines 2020, 8(3), 438; https://doi.org/10.3390/vaccines8030438 - 05 Aug 2020

Abstract

Innate responses provide the first line of defense against viral infections, including the influenza virus at mucosal surfaces. Communication and interaction between different host cells at the early stage of viral infections determine the quality and magnitude of immune responses against the invading virus. The release of membrane-encapsulated extracellular vesicles (EVs), from host cells, is defined as a refined system of cell-to-cell communication. EVs contain a diverse array of biomolecules, including microRNAs (miRNAs). We hypothesized that the activation of the tracheal cells with different stimuli impacts the cellular and EV miRNA profiles. Chicken tracheal rings were stimulated with polyI:C and LPS from Escherichia coli 026:B6 or infected with low pathogenic avian influenza virus H4N6. Subsequently, miRNAs were isolated from chicken tracheal cells or from EVs released from chicken tracheal cells. Differentially expressed (DE) miRNAs were identified in treated groups when compared to the control group. Our results demonstrated that there were 67 up-regulated miRNAs, 157 down-regulated miRNAs across all cellular and EV samples. In the next step, several genes or pathways targeted by DE miRNAs were predicted. Overall, this study presented a global miRNA expression profile in chicken tracheas in response to avian influenza viruses (AIV) and toll-like receptor (TLR) ligands. The results presented predicted the possible roles of some DE miRNAs in the induction of antiviral responses. The DE candidate miRNAs, including miR-146a, miR-146b, miR-205a, miR-205b and miR-449, can be investigated further for functional validation studies and to be used as novel prophylactic and therapeutic targets in tailoring or enhancing antiviral responses against AIV. Full article

(This article belongs to the Special Issue Avian Influenza Virus: New Strategies to Elicit Immune Responses and to Prevent and Control Infection)

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Open AccessArticle

Vaccination of Mice with a Novel Trypsin from Trichinella spiralis Elicits the Immune Protection against Larval Challenge

Yao Zhang ,

Jie Zeng ,

Yan Yan Song ,

Shao Rong Long ,

Ruo Dan Liu ,

Peng Jiang ,

Xi Zhang ,

Jing Cui and

Zhong Quan Wang

Vaccines 2020, 8(3), 437; https://doi.org/10.3390/vaccines8030437 - 05 Aug 2020

Abstract

Trichinella spiralis is a major foodborne parasite and has a serious threat to meat safety. Development of anti-Trichinella vaccines is prospective to eliminate Trichinella infection in food animal. The aim of this study was to assess the biological properties of a novel T. spiralis trypsin (TsT) and its elicited immune protection against larval challenge. The cDNA sequence of TsT gene was cloned and expressed. Western blotting showed rTsT was identified by infection serum and anti-TsT serum. RT-PCR results revealed that TsT gene was transcribed at diverse T. spiralis lifecycle stages. The IIFT results showed that natural TsT was principally expressed at epicuticle of 5-6 day adult worms, indicating that TsT is a worm somatic antigen and adult-stage specific surface antigen. Vaccination of mice with rTsT triggered an evident humoral immune response (high levels of serum IgG, IgG1/IgG2a, and enteral sIgA), and it also induced the systemic and enteral local cellular immune response, demonstrated by an significantly elevation of cytokines IFN-γ and IL-4. The mice vaccinated with rTsT exhibited a 33.17% reduction of enteral adult worms and a 37.80% reduction of muscle larvae after larval challenge. The results showed that TsT might be considered as a candidate target antigen for anti-T. spiralis vaccines. Full article

(This article belongs to the Special Issue Evaluation of Vaccine Immunogenicity)

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Open AccessPerspective

Natural Self-Ligand Gamma Delta T Cell Receptors (γδTCRs) Insight: The Potential of Induced IgG

Thamires Rodrigues de Sousa and

Jefferson Russo Victor

Vaccines 2020, 8(3), 436; https://doi.org/10.3390/vaccines8030436 - 04 Aug 2020

Abstract

A γδ T cell acquires functional properties in response to the gamma delta T cell receptor γδTCR signal strength during its development in the thymus. The elucidation of the potential ligands of γδ T cell receptors are of extreme importance; however, they are still not understood. Here we revise the actual state of the art of candidates to exert the function of γδTCR ligands, and propose a theoretical contribution about new potential ligands of γδTCRs, based on biological and hypothetical pieces of evidence in the literature. In conclusion, we hypothetically suggest a possible role of induced antibodies according to the individual’s immune status, mainly of the IgG subclass, acting as γδTCR ligands. Considering that IgG production is involved in some essential immunotherapy protocols, and almost all vaccination protocols, our discussion opens a new and broad field to further exploration. Full article

(This article belongs to the Special Issue Genomic Medicine and Advances in Vaccine Technology and Development in the Developing and Developed World)

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Open AccessArticle

Maximization of Livestock Anthrax Vaccination Coverage in Bangladesh: An Alternative Approach

M. Shahjahan A. Sarker ,

Mohamed E. El Zowalaty ,

M. Ahosanul Haque Shahid ,

M. Asaduzzaman Sarker ,

M. Bahanur Rahman ,

Josef D. Järhult and

K. H. M. Nazmul Hussain Nazir

Vaccines 2020, 8(3), 435; https://doi.org/10.3390/vaccines8030435 - 04 Aug 2020

Abstract

Low vaccination coverage of livestock is one of the major challenges to control anthrax in Bangladesh. This study was conducted to assess an alternate approach to maximize vaccination coverage. The method included traditional vaccination campaigns, livestock census, interviews, focus group discussions of cattle farmers, vaccination and livestock personnel, and validation workshops. It was observed that a mass vaccination program covered only 44% of the cattle population. It was found that 54.1% of the respondents did not bring their cattle to mass vaccination programs due to the difficulties of handling cattle and that there was no male member in the household. Only 12.5% of respondents acknowledged that they were not aware of the vaccine, and 3% of the respondents claimed that they ignored vaccination due to cost. All of the respondents from livestock personnel agreed that manpower was not enough to cover the total area. Further, 20% of vaccinators mentioned that they did not get enough vaccines. For an effective vaccination program, 58.33% of respondents recommended door-to-door service, and 54.16% of respondents suggested to arrange regular vaccination campaigns in six-month intervals. Thus, regular campaigns with door-to-door vaccination services are suggested to control anthrax outbreaks in Bangladesh. Full article

(This article belongs to the Section Veterinary Vaccines)

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Open AccessReview

Influenza A Virus Vaccination: Immunity, Protection, and Recent Advances Toward A Universal Vaccine

Christopher E. Lopez and

Kevin L. Legge

Vaccines 2020, 8(3), 434; https://doi.org/10.3390/vaccines8030434 - 03 Aug 2020

Abstract

Influenza virus infections represent a serious public health threat and account for significant morbidity and mortality worldwide due to seasonal epidemics and periodic pandemics. Despite being an important countermeasure to combat influenza virus and being highly efficacious when matched to circulating influenza viruses, current preventative strategies of vaccination against influenza virus often provide incomplete protection due the continuous antigenic drift/shift of circulating strains of influenza virus. Prevention and control of influenza virus infection with vaccines is dependent on the host immune response induced by vaccination and the various vaccine platforms induce different components of the local and systemic immune response. This review focuses on the immune basis of current (inactivated influenza vaccines (IIV) and live attenuated influenza vaccines (LAIV)) as well as novel vaccine platforms against influenza virus. Particular emphasis will be placed on how each platform induces cross-protection against heterologous influenza viruses, as well as how this immunity compares to and contrasts from the “gold standard” of immunity generated by natural influenza virus infection. Full article

(This article belongs to the Special Issue Development of Cross-Protective Vaccines)

Open AccessArticle

Lipid Nanoparticle Acts as a Potential Adjuvant for Influenza Split Vaccine without Inducing Inflammatory Responses

Daiki Omata ,

Ryo Suzuki and

Yasuo Yoshioka

Vaccines 2020, 8(3), 433; https://doi.org/10.3390/vaccines8030433 - 03 Aug 2020

Abstract

Vaccination is a critical and reliable strategy for controlling the spread of influenza viruses in populations. Conventional seasonal split vaccines (SVs) for influenza evoke weaker immune responses than other types of vaccines, such as inactivated whole-virion vaccines, although SVs are highly safe compared to other types. Here, we assessed the potential of the lipid nanoparticle (LNP) we developed as an adjuvant for conventional influenza SV as an antigen in mice. The LNP did not induce the production of cytokines such as interleukin-6 (IL-6) and IL-12 p40 by dendritic cells or the expression of co-stimulatory molecules on these cells in vitro. In contrast, an SV adjuvanted with LNP improved SV-specific IgG1 and IgG2 responses and the Th1 response compared to the SV alone in mice. In addition, SV adjuvanted with an LNP gave superior protection against the influenza virus challenge over the SV alone and was as effective as SV adjuvanted with aluminum salts in mice. The LNP did not provoke inflammatory responses such as inflammatory cytokine production and inflammatory immune cell infiltration in mice, whereas aluminum salts induced inflammatory responses. These results suggest the potential of the LNP as an adjuvant without inflammatory responses for influenza SVs. Our strategy should be useful for developing influenza vaccines with enhanced efficacy and safety. Full article

(This article belongs to the Special Issue Vaccinology of Influenza Infection)

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