scholarly journals A self-amplifying mRNA COVID-19 vaccine drives potent and broad immune responses at low doses that protects non-human primates against SARS-CoV-2

2021 ◽  
Author(s):  
Amy R Rappaport ◽  
Sue-Jean Hong ◽  
Ciaran D Scallan ◽  
Leonid Gitlin ◽  
Arvin Akoopie ◽  
...  
Keyword(s):  
Immune Responses ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Geometric Mean ◽  
Low Doses ◽  
Vaccination Regimen ◽  
Preclinical Development ◽  
Boost Regimen ◽  
Boost Vaccination ◽  
Dose Levels

The coronavirus disease 2019 (COVID-19) pandemic continues to spread globally, highlighting the urgent need for safe and effective vaccines that could be rapidly mobilized to immunize large populations. We report the preclinical development of a self-amplifying mRNA (SAM) vaccine encoding a prefusion stabilized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein and demonstrate potent cellular and humoral immune responses at low doses in mice and rhesus macaques. The homologous prime-boost vaccination regimen of SAM at 3, 10 and 30 μg induced potent neutralizing antibody titers in rhesus macaques following two SAM vaccinations at all dose levels, with the 10 μg dose generating geometric mean titers (GMT) 48-fold greater than the GMT of a panel of SARS-CoV-2 convalescent human sera. Spike-specific T cell responses were observed at all dose levels. SAM vaccination provided protective efficacy against SARS-CoV-2 challenge as both a homologous prime-boost and as a single boost following ChAd prime, demonstrating reduction of viral replication in both the upper and lower airways. Protection was most effective with a SAM prime-boost vaccination regimen at 10 and 30 μg and with a ChAd/SAM heterologous prime-boost regimen. The SAM vaccine is currently being evaluated in clinical trials as both a homologous prime-boost regimen at low doses and as a boost following heterologous prime.

scholarly journals Effective Induction of Simian Immunodeficiency Virus-Specific Cytotoxic T Lymphocytes in Macaques by Using a Multiepitope Gene and DNA Prime-Modified Vaccinia Virus Ankara Boost Vaccination Regimen

1999 ◽  
Vol 73 (9) ◽  
pp. 7524-7532 ◽  
Author(s):  
Tomas Hanke ◽  
Rachel V. Samuel ◽  
Tom J. Blanchard ◽  
Veronica C. Neumann ◽  
Todd M. Allen ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Simian Immunodeficiency Virus ◽  
Rhesus Macaques ◽  
Peripheral Blood Lymphocytes ◽  
Vaccination Regimen ◽  
Boost Regimen ◽  
Boost Vaccination ◽  
Modified Vaccinia Virus Ankara ◽  
Immunodeficiency Virus

ABSTRACT DNA and modified vaccinia virus Ankara (MVA) are vaccine vehicles suitable and safe for use in humans. Here, by using a multicytotoxic T-lymphocyte (CTL) epitope gene and a DNA prime-MVA boost vaccination regimen, high levels of CTLs specific for a single simian immunodeficiency virus (SIV) gag-derived epitope were elicited in rhesus macaques. These vaccine-induced CTLs were capable of killing SIV-infected cells in vitro. Fluorescence-activated cell sorter analysis using soluble tetrameric major histocompatibility complex-peptide complexes showed that the vaccinated animals had 1 to 5% circulating CD8+ lymphocytes specific for the vaccine epitope, frequencies comparable to those in SIV-infected monkeys. Upon intrarectal challenge with pathogenic SIVmac251, no evidence for protection was observed in at least two of the three vaccinated animals. This study does not attempt to define correlates of protective immunity nor design a protective vaccine against immunodeficiency viruses, but it demonstrates clearly that the DNA prime-MVA boost regimen is an effective protocol for induction of CTLs in macaques. It also shows that powerful tools for studying the role of CTLs in the control of SIV and human immunodeficiency virus infections are now available: epitope-based vaccines, a protocol for an effective induction of CTLs in primates, and a simple and sensitive method for quantitation of epitope-specific T cells. The advantages of the DNA prime-MVA boost regimen as well as the correlations of tetramer staining of peripheral blood lymphocytes with CTL killing in vitro and postchallenge control of viremia are discussed.

scholarly journals Chimpanzee adenoviral vector prime-boost regimen elicits potent immune responses against Ebola virus in mice and rhesus macaques

2019 ◽  
Vol 8 (1) ◽  
pp. 1086-1097 ◽  
Author(s):  
Xi Yang ◽  
Xiang Wang ◽  
Yufeng Song ◽  
Ping Zhou ◽  
Dapeng Li ◽  
...  
Keyword(s):  
Immune Responses ◽  
Adenoviral Vector ◽  
Ebola Virus ◽  
Rhesus Macaques ◽  
Boost Regimen

scholarly journals A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates

2020 ◽  
Author(s):  
Annette B. Vogel ◽  
Isis Kanevsky ◽  
Ye Che ◽  
Kena A. Swanson ◽  
Alexander Muik ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Rhesus Macaques ◽  
Geometric Mean ◽  
Effective Vaccine ◽  
Phase 2 ◽  
Preclinical Development ◽  
Pivotal Phase ◽  
Cell Responses ◽  
Large Populations ◽  
The One

AbstractTo contain the coronavirus disease 2019 (COVID-19) pandemic, a safe and effective vaccine against the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is urgently needed in quantities sufficient to immunise large populations. In this study, we report the design, preclinical development, immunogenicity and anti-viral protective effect in rhesus macaques of the BNT162b2 vaccine candidate. BNT162b2 contains an LNP-formulated nucleoside-modified mRNA that encodes the spike glycoprotein captured in its prefusion conformation. After expression of the BNT162b2 coding sequence in cells, approximately 20% of the spike molecules are in the one-RBD ‘up’, two-RBD ‘down’ state. Immunisation of mice with a single dose of BNT162b2 induced dose level-dependent increases in pseudovirus neutralisation titers. Prime-boost vaccination of rhesus macaques elicited authentic SARS-CoV-2 neutralising geometric mean titers 10.2 to 18.0 times that of a SARS-CoV-2 convalescent human serum panel. BNT162b2 generated strong TH1 type CD4+ and IFNγ+ CD8+ T-cell responses in mice and rhesus macaques. The BNT162b2 vaccine candidate fully protected the lungs of immunised rhesus macaques from infectious SARS-CoV-2 challenge. BNT162b2 is currently being evaluated in a global, pivotal Phase 2/3 trial (NCT04368728).

scholarly journals Immunogenicity and Protective Efficacy of DNA Vaccines Expressing Rhesus Cytomegalovirus Glycoprotein B, Phosphoprotein 65-2, and Viral Interleukin-10 in Rhesus Macaques

2006 ◽  
Vol 81 (3) ◽  
pp. 1095-1109 ◽  
Author(s):  
Yujuan Yue ◽  
Amitinder Kaur ◽  
Meghan K. Eberhardt ◽  
Nadine Kassis ◽  
Shan Shan Zhou ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Dna Vaccines ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Interleukin 10 ◽  
Antibody Responses ◽  
Glycoprotein B ◽  
Viral Loads ◽  
Rhesus Cytomegalovirus

ABSTRACT Rhesus cytomegalovirus (RhCMV) infection of macaques exhibits strong similarities to human CMV (HCMV) persistence and pathogenesis. The immunogenicity of DNA vaccines encoding three RhCMV proteins (a truncated version of glycoprotein B lacking the transmembrane region and endodomain [gBΔTM], phosphoprotein 65-2 [pp65-2], and viral interleukin-10 [vIL-10]) was evaluated in rhesus macaques. Two groups of monkeys (four per group) were genetically immunized four times with a mixture of either pp65-2 and gBΔTM or pp65-2, vIL-10, and gBΔTM. The vaccinees developed anti-gB and anti-pp65-2 antibodies in addition to pp65-2 cellular responses after the second booster immunization, with rapid responses observed with subsequent DNA injections. Weak vIL-10 immune responses were detected in two of the four immunized animals. Neutralizing antibodies were detected in seven monkeys, although titers were weak compared to those observed in naturally infected animals. The immunized monkeys and naïve controls were challenged intravenously with 105 PFU of RhCMV. Anamnestic binding and neutralizing antibody responses were observed 1 week postchallenge in the vaccinees. DNA vaccination-induced immune responses significantly decreased peak viral loads in the immunized animals compared to those in the controls. No difference in peak viral loads was observed between the pp65-2/gBΔTM DNA- and pp65-2/vIL-10/gBΔTM-vaccinated groups. Antibody responses to nonvaccine antigens were lower postchallenge in both vaccine groups than in the controls, suggesting long-term control of RhCMV protein expression. These data demonstrated that DNA vaccines targeting the RhCMV homologues of HCMV gB and pp65 altered the course of acute and persistent RhCMV infection in a primate host.

scholarly journals 33. Intranasal M2SR (M2-deficient Single Replication) Live H3N2 Influenza Investigational Vaccine Induces Serum HAI & Broad Immune Responses in High Proportion of Adults

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S40-S41
Author(s):  
Joseph Eiden ◽  
Ruth Ellis ◽  
Carlos Fierro ◽  
Howard Schwartz ◽  
Mark Adams ◽  
...  
Keyword(s):  
Immune Responses ◽  
Geometric Mean ◽  
Surrogate Marker ◽  
Secretory Iga ◽  
Human Influenza ◽  
Dose Escalation Study ◽  
Challenge Study ◽  
Antibody Titers ◽  
Protection Against Infection ◽  
Dose Levels

Abstract Background A single intranasal (IN) dose of 108 TCID50 M2SR protected a responder subset of adults against infection and disease in a prior human influenza challenge study (EudraCT number: 2017-004971-30). Higher dose levels of M2SR were assessed in this phase 1b study to enhance immune responses and further increase protection levels in adults. Methods A double-blind, randomized, placebo-controlled dose escalation study (NCT03999554) was conducted at 4 US study sites with two different H3N2 M2SR vaccines that contained HA & NA from either A/Brisbane/10/2007 or A/Singapore/INFIMH-16–0019/2016. Serosusceptible 18–49 year old subjects (n = 206) received 2 IN doses of either saline or 1 of 3 different dose levels of vaccine (108 – 109 TCID50), administered 28 days apart. Results Study vaccination was well-tolerated at all dose levels. A single 109 dose of A/Singapore/2016 M2SR generated significantly increased serum HAI responses compared to the 108 dose of A/Brisbane/10/2007 M2SR that had provided protection against infection & illness in an earlier human influenza challenge study (Fig. 1). HAI titers ≥40 were achieved in 0%, 23% & 58% of subjects after the first dose of placebo, 108 or 109 M2SR, respectively (p< 0.003). Increases also were stimulated in serum microneutralization titers (MNT) to drifted strains of H3N2 (Fig 2) & in serum NAI (Fig 3) and mucosal sIgA (Fig 4) titers. Further increases in serum and mucosal immune response were noted after a 2nd IN vaccination. Proportion of subjects with seroprotective HAI titers after vaccination Proportion of subjects with increased microneutralization titers against drifted H3N2 viruses after vaccination Geometric mean fold rise in serum neuraminidase inhibition antibody titers after vaccination Conclusion An earlier clinical trial with a 108 dose of M2SR provided protection against infection and illness upon challenge with a highly drifted strain of H3N2. Protection correlated with vaccine induced serum MNT responses. In the current study, a single, 109 dose of M2SR significantly increased serum MNT, HAI & NAI titers as well as mucosal immune responses among greater proportions of study subjects. Since HAI, alone, is a well-accepted surrogate marker for vaccine protection against influenza, these broader enhancements indicate the potential for M2SR to protect against both matched and drifted strains of influenza in a high proportion of adults and strongly support clinical assessment in younger and older age groups as well as development of multivalent M2SR. Geometric mean fold rise in nasal mucosal secretory IgA antibody titers after vaccination Disclosures Joseph Eiden, MD, PhD, FluGen (Consultant) Ruth Ellis, MD, FluGen (Consultant) Roger Aitchison, ScM, FluGen (Consultant) Renee Herber, BS, FluGen (Employee) Pamuk Bilsel, PhD, FluGen (Employee)

scholarly journals Strong, but Age-Dependent, Protection Elicited by a Deoxyribonucleic Acid/Modified Vaccinia Ankara Simian Immunodeficiency Virus Vaccine

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Venkateswarlu Chamcha ◽  
Sunil Kannanganat ◽  
Sailaja Gangadhara ◽  
Rafiq Nabi ◽  
Pamela A. Kozlowski ◽  
...  
Keyword(s):  
Immune Responses ◽  
Simian Immunodeficiency Virus ◽  
Virus Vaccine ◽  
Deoxyribonucleic Acid ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Human Immunodeficiency Virus Vaccine ◽  
Immunodeficiency Virus ◽  
Age Dependent ◽  
Human Vaccine

Abstract Background.  In this study, we analyzed the protective efficacy of a simian immunodeficiency virus (SIV) macaque 239 (SIVmac239) analogue of the clinically tested GOVX-B11 deoxyribonucleic acid (DNA)/modified vaccinia Ankara (MVA) human immunodeficiency virus vaccine. Methods.  The tested vaccine used a DNA immunogen mutated to mimic the human vaccine and a regimen with DNA deliveries at weeks 0 and 8 and MVA deliveries at weeks 16 and 32. Twelve weekly rectal challenges with 0.3 animal infectious doses of SIV sootey mangabey E660 (SIVsmE660) were administered starting at 6 months after the last immunization. Results.  Over the first 6 rectal exposures to SIVsmE660, <10-year-old tripartite motif-containing protein 5 (TRIM5)α-permissive rhesus macaques showed an 80% reduction in per-exposure risk of infection as opposed to a 46% reduction in animals over 10 years old; and, over the 12 challenges, they showed a 72% as opposed to a 10% reduction. Analyses of elicited immune responses suggested that higher antibody responses in the younger animals had played a role in protection. Conclusions.  The simian analogue of the GOVX-B11 HIV provided strong protection against repeated rectal challenges in young adult macaques.

scholarly journals Vaccination strategy and anti - SARS-CoV-2 S titers in healthcare workers of the INT – IRCCS “Fondazione Pascale” Cancer Center (Naples, Italy)

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ernesta Cavalcanti ◽  
Maria Antonietta Isgrò ◽  
Domenica Rea ◽  
Lucia Di Capua ◽  
Giusy Trillò ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Healthcare Workers ◽  
Geometric Mean ◽  
Vaccination Strategy ◽  
Antibody Responses ◽  
Cancer Center ◽  
Serum Samples ◽  
Humoral Immune ◽  
History Of

Abstract Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of people globally, requiring the development of billions of different vaccine doses. The SARS-CoV-2 spike mRNA vaccine (named BNT162b2/Pfizer), authorized by the FDA, has shown high efficacy in preventing SARS-CoV-2 infection after administration of two doses in individuals 16 years of age and older. In the present study, we retrospectively evaluated the differences in the SARS-CoV-2 humoral immune response after vaccine administration in the two different cohorts of workers at the INT - IRCCS “Fondazione Pascale” Cancer Center (Naples, Italy): previously infected to SARS-CoV-2 subjects and not infected to SARS-CoV-2 subjects. Methods We determined specific anti-RBD (receptor-binding domain) titers against trimeric spike glycoprotein (S) of SARS-CoV-2 by Roche Elecsys Anti-SARS-CoV-2 S immunoassay in serum samples of 35 healthcare workers with a previous documented history of SARS-CoV-2 infection and 158 healthcare workers without, after 1 and 2 doses of vaccine, respectively. Moreover, geometric mean titers and relative fold changes (FC) were calculated. Results Both previously infected and not infected to SARS-CoV-2 subjects developed significant immune responses to SARS-CoV-2 after the administration of 1 and 2 doses of vaccine, respectively. Anti-S antibody responses to the first dose of vaccine were significantly higher in previously SARS-CoV-2-infected subjects in comparison to titers of not infected subjects after the first as well as the second dose of vaccine. Fold changes for subjects previously infected to SARS-CoV-2 was very modest, given the high basal antibody titer, as well as the upper limit of 2500.0 BAU/mL imposed by the Roche methods. Conversely, for naïve subjects, mean fold change following the first dose was low ($$ \overline{x} $$ x ¯ =1.6), reaching 3.8 FC in 72 subjects (45.6%) following the second dose. Conclusions The results showed that, as early as the first dose, SARS-CoV-2-infected individuals developed a remarkable and statistically significant immune response in comparison to those who did not contract the virus previously, suggesting the possibility of administering only one dose in previously SARS-CoV-2-infected subjects. FC for previously infected subjects should not be taken into account for the generally high pre-vaccination values. Conversely, FC for not infected subjects, after the second dose, were = 3.8 in > 45.0% of vaccinees, and ≤ 3.1 in 19.0%, the latter showing a potential susceptibility to further SARS-CoV-2 infection.

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