scholarly journals Neonatal and infant immunity for tuberculosis vaccine development: importance of age-matched animal models

2020 ◽  
Vol 13 (9) ◽  
pp. dmm045740
Author(s):  
Laylaa Ramos ◽  
Joan K. Lunney ◽  
Mercedes Gonzalez-Juarrero
Keyword(s):  
Animal Models ◽  
Immune Responses ◽  
Vaccine Development ◽  
Vaccine Candidates ◽  
Memory T Cell ◽  
Cell Responses ◽  
Good Safety Profile ◽  
Immune Mediated ◽  
Relative Utility ◽  
Infant Immune Response

ABSTRACTNeonatal and infant immunity differs from that of adults in both the innate and adaptive arms, which are critical contributors to immune-mediated clearance of infection and memory responses elicited during vaccination. The tuberculosis (TB) research community has openly admitted to a vacuum of knowledge about neonatal and infant immune responses to Mycobacterium tuberculosis (Mtb) infection, especially in the functional and phenotypic attributes of memory T cell responses elicited by the only available vaccine for TB, the Bacillus Calmette–Guérin (BCG) vaccine. Although BCG vaccination has variable efficacy in preventing pulmonary TB during adolescence and adulthood, 80% of endemic TB countries still administer BCG at birth because it has a good safety profile and protects children from severe forms of TB. As such, new vaccines must work in conjunction with BCG at birth and, thus, it is essential to understand how BCG shapes the immune system during the first months of life. However, many aspects of the neonatal and infant immune response elicited by vaccination with BCG remain unknown, as only a handful of studies have followed BCG responses in infants. Furthermore, most animal models currently used to study TB vaccine candidates rely on adult-aged animals. This presents unique challenges when transitioning to human trials in neonates or infants. In this Review, we focus on vaccine development in the field of TB and compare the relative utility of animal models used thus far to study neonatal and infant immunity. We encourage the development of neonatal animal models for TB, especially the use of pigs.

scholarly journals A PBMC-Based System to Assess Human T Cell Responses to Influenza Vaccine Candidates In Vitro

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 181 ◽  
Author(s):  
Gabriela Tapia-Calle ◽  
Philip A. Born ◽  
Georgia Koutsoumpli ◽  
Martin Ignacio Gonzalez-Rodriguez ◽  
Wouter L. J. Hinrichs ◽  
...  
Keyword(s):  
Clinical Trials ◽  
T Cell ◽  
Animal Models ◽  
Vaccine Development ◽  
Animal Experiments ◽  
T Cell Responses ◽  
T Cell Subsets ◽  
Vaccine Candidates ◽  
Cell Responses

Vaccine development is an expensive and time-consuming process that heavily relies on animal models. Yet, vaccine candidates that have previously succeeded in animal experiments often fail in clinical trials questioning the predictive value of animal models. Alternative assay systems that can add to the screening and evaluation of functional characteristics of vaccines in a human context before embarking on costly clinical trials are therefore urgently needed. In this study, we have established an in vitro system consisting of long-term cultures of unfractionated peripheral blood mononuclear cells (PBMCs) from healthy volunteers to assess (recall) T cell responses to vaccine candidates. We observed that different types of influenza vaccines (whole inactivated virus (WIV), split, and peptide vaccines) were all able to stimulate CD4 and CD8 T cell responses but to different extents in line with their reported in vivo properties. In-depth analyses of different T cell subsets revealed that the tested vaccines evoked mainly recall responses as indicated by the fact that the vast majority of the responding T cells had a memory phenotype. Furthermore, we observed vaccine-induced activation of T follicular helper cells, which are associated with the induction of humoral immune responses. Our results demonstrate the suitability of the established PBMC-based system for the in vitro evaluation of memory T cell responses to vaccines and the comparison of vaccine candidates in a human immune cell context. As such, it can help to bridge the gap between animal experiments and clinical trials and assist in the selection of promising vaccine candidates, at least for recall antigens.

scholarly journals Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice

Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 125 ◽  
Author(s):  
Entao Li ◽  
Feihu Yan ◽  
Pei Huang ◽  
Hang Chi ◽  
Shengnan Xu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Antibody Response ◽  
Rabies Virus ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Viral Vector ◽  
Vaccine Vector ◽  
Vaccine Candidates ◽  
Cellular Immune Responses ◽  
Cellular Immune

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

scholarly journals Sustained Specific and Cross-Reactive T Cell Responses to Zika and Dengue Virus NS3 in West Africa

2018 ◽  
Vol 92 (7) ◽  
Author(s):  
Bobby Brooke Herrera ◽  
Wen-Yang Tsai ◽  
Charlotte A. Chang ◽  
Donald J. Hamel ◽  
Wei-Kung Wang ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Dengue Virus ◽  
Zika Virus ◽  
Cell Response ◽  
Vaccine Development ◽  
T Cell Responses ◽  
T Cell Response ◽  
Zikv Infection ◽  
Cell Responses

ABSTRACT Recent studies on the role of T cells in Zika virus (ZIKV) infection have shown that T cell responses to Asian ZIKV infection are important for protection, and that previous dengue virus (DENV) exposure amplifies the protective T cell response to Asian ZIKV. Human T cell responses to African ZIKV infection, however, remain unexplored. Here, we utilized the modified anthrax toxin delivery system to develop a flavivirus enzyme-linked immunosorbent spot (ELISPOT) assay. Using human ZIKV and DENV samples from Senegal, West Africa, our results demonstrate specific and cross-reactive T cell responses to nonstructural protein 3 (NS3). Specifically, we found that T cell responses to NS3 protease are ZIKV and DENV specific, but responses to NS3 helicase are cross-reactive. Sequential sample analyses revealed immune responses sustained many years after infection. These results have important implications for African ZIKV/DENV vaccine development, as well as for potential flavivirus diagnostics based on T cell responses. IMPORTANCE The recent Zika virus (ZIKV) epidemic in Latin America and the associated congenital microcephaly and Guillain-Barré syndrome have raised questions as to why we have not recognized these distinct clinical diseases in Africa. The human immunologic response to ZIKV and related flaviviruses in Africa represents a research gap that may shed light on the mechanisms contributing to protection. The goal of our study was to develop an inexpensive assay to detect and characterize the T cell response to African ZIKV and DENV. Our data show long-term specific and cross-reactive human immune responses against African ZIKV and DENV, suggesting the usefulness of a diagnostic based on the T cell response. Additionally, we show that prior flavivirus exposure influences the magnitude of the T cell response. The identification of immune responses to African ZIKV and DENV is of relevance to vaccine development.

scholarly journals Differential CD4+ versus CD8+ T-Cell Responses Elicited by Different Poxvirus-Based Human Immunodeficiency Virus Type 1 Vaccine Candidates Provide Comparable Efficacies in Primates

2008 ◽  
Vol 82 (6) ◽  
pp. 2975-2988 ◽  
Author(s):  
Petra Mooij ◽  
Sunita S. Balla-Jhagjhoorsingh ◽  
Gerrit Koopman ◽  
Niels Beenhakker ◽  
Patricia van Haaften ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Immune Responses ◽  
Vaccinia Virus ◽  
T Cell Responses ◽  
Vaccine Candidates ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Poxvirus vectors have proven to be highly effective for boosting immune responses in diverse vaccine settings. Recent reports reveal marked differences in the gene expression of human dendritic cells infected with two leading poxvirus-based human immunodeficiency virus (HIV) vaccine candidates, New York vaccinia virus (NYVAC) and modified vaccinia virus Ankara (MVA). To understand how complex genomic changes in these two vaccine vectors translate into antigen-specific systemic immune responses, we undertook a head-to-head vaccine immunogenicity and efficacy study in the pathogenic HIV type 1 (HIV-1) model of AIDS in Indian rhesus macaques. Differences in the immune responses in outbred animals were not distinguished by enzyme-linked immunospot assays, but differences were distinguished by multiparameter fluorescence-activated cell sorter analysis, revealing a difference between the number of animals with both CD4+ and CD8+ T-cell responses to vaccine inserts (MVA) and those that elicit a dominant CD4+ T-cell response (NYVAC). Remarkably, vector-induced differences in CD4+/CD8+ T-cell immune responses persisted for more than a year after challenge and even accompanied antigenic modulation throughout the control of chronic infection. Importantly, strong preexposure HIV-1/simian immunodeficiency virus-specific CD4+ T-cell responses did not prove deleterious with respect to accelerated disease progression. In contrast, in this setting, animals with strong vaccine-induced polyfunctional CD4+ T-cell responses showed efficacies similar to those with stronger CD8+ T-cell responses.

scholarly journals COVID-19 Basics and Vaccine Development with a Canadian Perspective

2020 ◽  
Author(s):  
Marina Liu ◽  
Xiongbiao Chen
Keyword(s):  
Animal Models ◽  
Severe Acute Respiratory Syndrome ◽  
Clinical Evaluation ◽  
Vaccine Development ◽  
Specific Treatment ◽  
Vaccine Candidates ◽  
Preclinical Evaluation ◽  
Canadian Perspective ◽  
Basic Biology

The ongoing coronavirus disease 2019 (COVID-19) pandemic is a rapidly evolving situation. New discoveries about COVID-19 and its causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continue to deepen the understanding of this novel disease. As there is currently no COVID-19 specific treatment, isolation is the most effective method to prevent transmission. Moreover, development of a safe and effective COVID-19 vaccine will be instrumental in reinstating pre-COVID-19 conditions. As of July 31, 2020, there are at least 139 vaccine candidates from around the globe are in preclinical evaluation, with another 26 undergoing clinical evaluation. This paper aims to review the basics of COVID-19, including epidemiology, basic biology of SARS-CoV-2, and transmission. We also review COVID-19 vaccine development, including animal models, platforms under development, and vaccine development in Canada.

scholarly journals Robust immune responses after one dose of BNT162b2 mRNA vaccine dose in SARS-CoV-2 experienced individuals

2021 ◽  
Author(s):  
Marie I. Samanovic ◽  
Amber R. Cornelius ◽  
Sophie L. Gray-Gaillard ◽  
Joseph Richard Allen ◽  
Trishala Karmacharya ◽  
...  
Keyword(s):  
Immune Responses ◽  
Protective Efficacy ◽  
Vaccine Dose ◽  
Prior History ◽  
Vaccine Candidates ◽  
Antibody Secreting Cell ◽  
Cell Responses ◽  
Efficacy Trials ◽  
History Of ◽  
Humoral Responses

ABSTRACTThe use of COVID-19 vaccines will play a major role in helping to end the pandemic that has killed millions worldwide. COVID-19 vaccine candidates have resulted in robust humoral responses and protective efficacy in human trials, but efficacy trials excluded individuals with prior diagnosis of COVID-19. As a result, little is known about how immune responses induced by mRNA vaccine candidates differ in individuals who recovered from COVID-19. Here, we evaluated longitudinal immune responses to two-dose BNT162b2 mRNA vaccination in 13 adults who recovered from COVID-19, compared to 19 adults who did not have prior COVID-19 diagnosis. Consistent with prior studies of mRNA vaccines, we observed robust cytotoxic CD8 T cell responses in both cohorts. Furthermore, SARS-CoV-2-naive individuals had progressive increases in humoral and antigen-specific antibody-secreting cell (ASC) responses following each dose of vaccine, whereas SARS-CoV-2-experienced individuals demonstrated strong humoral and antigen-specific ASC responses to the first dose but muted responses to the second dose of the vaccine for the time points studied. Together, these data highlight the relevance of immunological history for understanding vaccine immune responses and may have significant implications for personalizing mRNA vaccination regimens used to prevent COVID-19.One Sentence SummaryPrior history of COVID-19 affects adaptive immune responses to mRNA vaccination.

scholarly journals Cellular and Humoral Immunogenicity of a Candidate DNA Vaccine Expressing SARS-CoV-2 Spike Subunit 1

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 852
Author(s):  
Khalid A. Alluhaybi ◽  
Rahaf H. Alharbi ◽  
Rowa Y. Alhabbab ◽  
Najwa D. Aljehani ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Immune Responses ◽  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Specific Igg ◽  
Cellular Immune ◽  
Different Doses

The urgent need for effective, safe and equitably accessible vaccines to tackle the ongoing spread of COVID-19 led researchers to generate vaccine candidates targeting varieties of immunogens of SARS-CoV-2. Because of its crucial role in mediating binding and entry to host cell and its proven safety profile, the subunit 1 (S1) of the spike protein represents an attractive immunogen for vaccine development. Here, we developed and assessed the immunogenicity of a DNA vaccine encoding the SARS-CoV-2 S1. Following in vitro confirmation and characterization, the humoral and cellular immune responses of our vaccine candidate (pVAX-S1) was evaluated in BALB/c mice using two different doses, 25 µg and 50 µg. Our data showed high levels of SARS-CoV-2 specific IgG and neutralizing antibodies in mice immunized with three doses of pVAX-S1. Analysis of the induced IgG subclasses showed a Th1-polarized immune response, as demonstrated by the significant elevation of spike-specific IgG2a and IgG2b, compared to IgG1. Furthermore, we found that the immunization of mice with three doses of 50 µg of pVAX-S1 could elicit significant memory CD4+ and CD8+ T cell responses. Taken together, our data indicate that pVAX-S1 is immunogenic and safe in mice and is worthy of further preclinical and clinical evaluation.

scholarly journals Targeting Antigens to Dendritic Cell Receptors for Vaccine Development

2013 ◽  
Vol 2013 ◽  
pp. 1-22 ◽  
Author(s):  
Vasso Apostolopoulos ◽  
Theresia Thalhammer ◽  
Andreas G. Tzakos ◽  
Lily Stojanovska
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
Immune Responses ◽  
Vaccine Development ◽  
T Cell Responses ◽  
Dual Function ◽  
Antigen Delivery ◽  
Surface Receptors ◽  
Mhc Molecules ◽  
Cell Responses

Dendritic cells (DCs) are highly specialized antigen presenting cells of the immune system which play a key role in regulating immune responses. Depending on the method of antigen delivery, DCs stimulate immune responses or induce tolerance. As a consequence of the dual function of DCs, DCs are studied in the context of immunotherapy for both cancer and autoimmune diseases. In vaccine development, a major aim is to induce strong, specific T-cell responses. This is achieved by targeting antigen to cell surface molecules on DCs that efficiently channel the antigen into endocytic compartments for loading onto MHC molecules and stimulation of T-cell responses. The most attractive cell surface receptors, expressed on DCs used as targets for antigen delivery for cancer and other diseases, are discussed.

scholarly journals Integrating fish models in tuberculosis vaccine development

2020 ◽  
Vol 13 (8) ◽  
pp. dmm045716
Author(s):  
Anni K. Saralahti ◽  
Meri I. E. Uusi-Mäkelä ◽  
Mirja T. Niskanen ◽  
Mika Rämet
Keyword(s):  
Immune Responses ◽  
Vaccine Development ◽  
Bacillus Calmette Guerin ◽  
Antibiotic Resistant ◽  
Vaccine Candidates ◽  
Preclinical Evaluation ◽  
Vaccination Strategies ◽  
Resistant Strains ◽  
New Vaccines

ABSTRACTTuberculosis is a chronic infection by Mycobacterium tuberculosis that results in over 1.5 million deaths worldwide each year. Currently, there is only one vaccine against tuberculosis, the Bacillus Calmette–Guérin (BCG) vaccine. Despite widespread vaccination programmes, over 10 million new M. tuberculosis infections are diagnosed yearly, with almost half a million cases caused by antibiotic-resistant strains. Novel vaccination strategies concentrate mainly on replacing BCG or boosting its efficacy and depend on animal models that accurately recapitulate the human disease. However, efforts to produce new vaccines against an M. tuberculosis infection have encountered several challenges, including the complexity of M. tuberculosis pathogenesis and limited knowledge of the protective immune responses. The preclinical evaluation of novel tuberculosis vaccine candidates is also hampered by the lack of an appropriate animal model that could accurately predict the protective effect of vaccines in humans. Here, we review the role of zebrafish (Danio rerio) and other fish models in the development of novel vaccines against tuberculosis and discuss how these models complement the more traditional mammalian models of tuberculosis.

scholarly journals African Green Monkeys Recapitulate the Clinical Experience with Replication of Live Attenuated Pandemic Influenza Virus Vaccine Candidates

2014 ◽  
Vol 88 (14) ◽  
pp. 8139-8152 ◽  
Author(s):  
Yumiko Matsuoka ◽  
Amorsolo Suguitan ◽  
Marlene Orandle ◽  
Myeisha Paskel ◽  
Kobporn Boonnak ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Animal Models ◽  
Avian Influenza ◽  
Immune Responses ◽  
Respiratory Tract ◽  
Nonhuman Primate ◽  
Protective Efficacy ◽  
Wild Type ◽  
Vaccine Candidates ◽  
Green Monkeys

ABSTRACTLive attenuated cold-adapted (ca) H5N1, H7N3, H6N1, and H9N2 influenza vaccine viruses replicated in the respiratory tract of mice and ferrets, and 2 doses of vaccines were immunogenic and protected these animals from challenge infection with homologous and heterologous wild-type (wt) viruses of the corresponding subtypes. However, when these vaccine candidates were evaluated in phase I clinical trials, there were inconsistencies between the observations in animal models and in humans. The vaccine viruses did not replicate well and immune responses were variable in humans, even though the study subjects were seronegative with respect to the vaccine viruses before vaccination. Therefore, we sought a model that would better reflect the findings in humans and evaluated African green monkeys (AGMs) as a nonhuman primate model. The distribution of sialic acid (SA) receptors in the respiratory tract of AGMs was similar to that in humans. We evaluated the replication ofwtandcaviruses of avian influenza (AI) virus subtypes H5N1, H6N1, H7N3, and H9N2 in the respiratory tract of AGMs. All of thewtviruses replicated efficiently, while replication of thecavaccine viruses was restricted to the upper respiratory tract. Interestingly, the patterns and sites of virus replication differed among the different subtypes. We also evaluated the immunogenicity and protective efficacy of H5N1, H6N1, H7N3, and H9N2cavaccines. Protection fromwtvirus challenge correlated well with the level of serum neutralizing antibodies. Immune responses were slightly better when vaccine was delivered by both intranasal and intratracheal delivery than when it was delivered intranasally by sprayer. We conclude that live attenuated pandemic influenza virus vaccines replicate similarly in AGMs and human subjects and that AGMs may be a useful model to evaluate the replication ofcavaccine candidates.IMPORTANCEFerrets and mice are commonly used for preclinical evaluation of influenza vaccines. However, we observed significant inconsistencies between observations in humans and in these animal models. We used African green monkeys (AGMs) as a nonhuman primate (NHP) model for a comprehensive and comparative evaluation of pairs of wild-type and pandemic live attenuated influenza virus vaccines (pLAIV) representing four subtypes of avian influenza viruses and found that pLAIVs replicate similarly in AGMs and humans and that AGMs can be useful for evaluation of the protective efficacy of pLAIV.

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