Publications by authors named "Makda Gebre"

21 Publications

  • Page 1 of 1

Durable Humoral and Cellular Immune Responses Following Ad26.COV2.S Vaccination for COVID-19.

medRxiv 2021 Jul 7. Epub 2021 Jul 7.

Janssen Vaccines & Prevention, Leiden, The Netherlands.

Interim immunogenicity and efficacy data for the Ad26.COV2.S vaccine for COVID-19 have recently been reported . We describe here the 8-month durability of humoral and cellular immune responses in 20 individuals who received one or two doses of 5Ã-10 vp or 10 vp Ad26.COV2.S and in 5 participants who received placebo . We evaluated antibody and T cell responses on day 239, which was 8 months after the single-shot vaccine regimen (N=10) or 6 months after the two-shot vaccine regimen (N=10), although the present study was not powered to compare these regimens . We also report neutralizing antibody responses against the parental SARS-CoV-2 WA1/2020 strain as well as against the SARS-CoV-2 variants D614G, B.1.1.7 (alpha), B.1.617.1 (kappa), B.1.617.2 (delta), P.1 (gamma), B.1.429 (epsilon), and B.1.351 (beta).
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http://dx.doi.org/10.1101/2021.07.05.21259918DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282116PMC
July 2021

Immunogenicity of COVID-19 mRNA Vaccines in Pregnant and Lactating Women.

JAMA 2021 06;325(23):2370-2380

Harvard Medical School, Boston, Massachusetts.

Importance: Pregnant women are at increased risk of morbidity and mortality from COVID-19 but have been excluded from the phase 3 COVID-19 vaccine trials. Data on vaccine safety and immunogenicity in these populations are therefore limited.

Objective: To evaluate the immunogenicity of COVID-19 messenger RNA (mRNA) vaccines in pregnant and lactating women, including against emerging SARS-CoV-2 variants of concern.

Design, Setting, And Participants: An exploratory, descriptive, prospective cohort study enrolled 103 women who received a COVID-19 vaccine from December 2020 through March 2021 and 28 women who had confirmed SARS-CoV-2 infection from April 2020 through March 2021 (the last follow-up date was March 26, 2021). This study enrolled 30 pregnant, 16 lactating, and 57 neither pregnant nor lactating women who received either the mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines and 22 pregnant and 6 nonpregnant unvaccinated women with SARS-CoV-2 infection.

Main Outcomes And Measures: SARS-CoV-2 receptor binding domain binding, neutralizing, and functional nonneutralizing antibody responses from pregnant, lactating, and nonpregnant women were assessed following vaccination. Spike-specific T-cell responses were evaluated using IFN-γ enzyme-linked immunospot and multiparameter intracellular cytokine-staining assays. Humoral and cellular immune responses were determined against the original SARS-CoV-2 USA-WA1/2020 strain as well as against the B.1.1.7 and B.1.351 variants.

Results: This study enrolled 103 women aged 18 to 45 years (66% non-Hispanic White) who received a COVID-19 mRNA vaccine. After the second vaccine dose, fever was reported in 4 pregnant women (14%; SD, 6%), 7 lactating women (44%; SD, 12%), and 27 nonpregnant women (52%; SD, 7%). Binding, neutralizing, and functional nonneutralizing antibody responses as well as CD4 and CD8 T-cell responses were present in pregnant, lactating, and nonpregnant women following vaccination. Binding and neutralizing antibodies were also observed in infant cord blood and breast milk. Binding and neutralizing antibody titers against the SARS-CoV-2 B.1.1.7 and B.1.351 variants of concern were reduced, but T-cell responses were preserved against viral variants.

Conclusion And Relevance: In this exploratory analysis of a convenience sample, receipt of a COVID-19 mRNA vaccine was immunogenic in pregnant women, and vaccine-elicited antibodies were transported to infant cord blood and breast milk. Pregnant and nonpregnant women who were vaccinated developed cross-reactive antibody responses and T-cell responses against SARS-CoV-2 variants of concern.
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http://dx.doi.org/10.1001/jama.2021.7563DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120446PMC
June 2021

Novel approaches for vaccine development.

Cell 2021 03;184(6):1589-1603

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA; Massachusetts Consortium on Pathogen Readiness, Boston, MA, USA. Electronic address:

Vaccines are critical tools for maintaining global health. Traditional vaccine technologies have been used across a wide range of bacterial and viral pathogens, yet there are a number of examples where they have not been successful, such as for persistent infections, rapidly evolving pathogens with high sequence variability, complex viral antigens, and emerging pathogens. Novel technologies such as nucleic acid and viral vector vaccines offer the potential to revolutionize vaccine development as they are well-suited to address existing technology limitations. In this review, we discuss the current state of RNA vaccines, recombinant adenovirus vector-based vaccines, and advances from biomaterials and engineering that address these important public health challenges.
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http://dx.doi.org/10.1016/j.cell.2021.02.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049514PMC
March 2021

Deletion of the SARS-CoV-2 Spike Cytoplasmic Tail Increases Infectivity in Pseudovirus Neutralization Assays.

J Virol 2021 Mar 16. Epub 2021 Mar 16.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA

Pseudotyped viruses are valuable tools for studying virulent or lethal viral pathogens that need to be handled in biosafety level 3 (BSL-3) or higher facilities. With the explosive spread of the coronavirus disease 2019 (COVID-19) pandemic, the establishment of a BSL-2 adapted SARS-CoV-2 pseudovirus neutralization assay is needed to facilitate the development of countermeasures. Here we describe an approach to generate a single-round lentiviral vector-based SARS-CoV-2 pseudovirus, which produced a signal more than 2 logs above background. Specifically, a SARS-CoV-2 spike variant with a cytoplasmic tail deletion of 13 amino acids, termed SΔCT13, conferred enhanced spike incorporation into pseudovirions and increased viral entry into cells as compared with full-length spike (S). We further compared S and SΔCT13 in terms of their sensitivity to vaccine sera, purified convalescent IgG, hACE2-mIgG, and the virus entry inhibitor BafA1. We developed a SΔCT13-based pseudovirus neutralization assay and defined key assay characteristics, including linearity, limit of detection, and intra- and intermediate-assay precision. Our data demonstrate that the SΔCT13-based pseudovirus shows enhanced infectivity in target cells, which will facilitate the assessment of humoral immunity to SARS-CoV-2 infection, antibody therapeutics, and vaccination. This pseudovirus neutralization assay can also be readily adapted to SARS-CoV-2 variants that emerge.SARS-CoV-2 is the etiologic agent of the COVID-19 pandemic. The development of a high throughput pseudovirus neutralization assay is critical for the development of vaccines and immune-based therapeutics. In this study, we show that deletion of the cytoplasmic tail of the SARS-CoV-2 spike leads to pseudoviruses with enhanced infectivity. This SΔCT13-based pseudovirus neutralization assay should be broadly useful for the field.
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http://dx.doi.org/10.1128/JVI.00044-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8139703PMC
March 2021

Immunogenicity of the Ad26.COV2.S Vaccine for COVID-19.

JAMA 2021 04;325(15):1535-1544

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, Massachusetts.

Importance: Control of the global COVID-19 pandemic will require the development and deployment of safe and effective vaccines.

Objective: To evaluate the immunogenicity of the Ad26.COV2.S vaccine (Janssen/Johnson & Johnson) in humans, including the kinetics, magnitude, and phenotype of SARS-CoV-2 spike-specific humoral and cellular immune responses.

Design, Setting, And Participants: Twenty-five participants were enrolled from July 29, 2020, to August 7, 2020, and the follow-up for this day 71 interim analysis was completed on October 3, 2020; follow-up to assess durability will continue for 2 years. This study was conducted at a single clinical site in Boston, Massachusetts, as part of a randomized, double-blind, placebo-controlled phase 1 clinical trial of Ad26.COV2.S.

Interventions: Participants were randomized to receive 1 or 2 intramuscular injections with 5 × 1010 viral particles or 1 × 1011 viral particles of Ad26.COV2.S vaccine or placebo administered on day 1 and day 57 (5 participants in each group).

Main Outcomes And Measures: Humoral immune responses included binding and neutralizing antibody responses at multiple time points following immunization. Cellular immune responses included immunospot-based and intracellular cytokine staining assays to measure T-cell responses.

Results: Twenty-five participants were randomized (median age, 42; age range, 22-52; 52% women, 44% male, 4% undifferentiated), and all completed the trial through the day 71 interim end point. Binding and neutralizing antibodies emerged rapidly by day 8 after initial immunization in 90% and 25% of vaccine recipients, respectively. By day 57, binding and neutralizing antibodies were detected in 100% of vaccine recipients after a single immunization. On day 71, the geometric mean titers of spike-specific binding antibodies were 2432 to 5729 and the geometric mean titers of neutralizing antibodies were 242 to 449 in the vaccinated groups. A variety of antibody subclasses, Fc receptor binding properties, and antiviral functions were induced. CD4+ and CD8+ T-cell responses were induced.

Conclusion And Relevance: In this phase 1 study, a single immunization with Ad26.COV2.S induced rapid binding and neutralization antibody responses as well as cellular immune responses. Two phase 3 clinical trials are currently underway to determine the efficacy of the Ad26.COV2.S vaccine.

Trial Registration: ClinicalTrials.gov Identifier: NCT04436276.
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http://dx.doi.org/10.1001/jama.2021.3645DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953339PMC
April 2021

Discrete SARS-CoV-2 antibody titers track with functional humoral stability.

Nat Commun 2021 02 15;12(1):1018. Epub 2021 Feb 15.

Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.

Antibodies serve as biomarkers of infection, but if sustained can confer long-term immunity. Yet, for most clinically approved vaccines, binding antibody titers only serve as a surrogate of protection. Instead, the ability of vaccine induced antibodies to neutralize or mediate Fc-effector functions is mechanistically linked to protection. While evidence has begun to point to persisting antibody responses among SARS-CoV-2 infected individuals, cases of re-infection have begun to emerge, calling the protective nature of humoral immunity against this highly infectious pathogen into question. Using a community-based surveillance study, we aimed to define the relationship between titers and functional antibody activity to SARS-CoV-2 over time. Here we report significant heterogeneity, but limited decay, across antibody titers amongst 120 identified seroconverters, most of whom had asymptomatic infection. Notably, neutralization, Fc-function, and SARS-CoV-2 specific T cell responses were only observed in subjects that elicited RBD-specific antibody titers above a threshold. The findings point to a switch-like relationship between observed antibody titer and function, where a distinct threshold of activity-defined by the level of antibodies-is required to elicit vigorous humoral and cellular response. This response activity level may be essential for durable protection, potentially explaining why re-infections occur with SARS-CoV-2 and other common coronaviruses.
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http://dx.doi.org/10.1038/s41467-021-21336-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884400PMC
February 2021

Correlates of protection against SARS-CoV-2 in rhesus macaques.

Nature 2021 02 4;590(7847):630-634. Epub 2020 Dec 4.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

Recent studies have reported the protective efficacy of both natural and vaccine-induced immunity against challenge with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in rhesus macaques. However, the importance of humoral and cellular immunity for protection against infection with SARS-CoV-2 remains to be determined. Here we show that the adoptive transfer of purified IgG from convalescent rhesus macaques (Macaca mulatta) protects naive recipient macaques against challenge with SARS-CoV-2 in a dose-dependent fashion. Depletion of CD8 T cells in convalescent macaques partially abrogated the protective efficacy of natural immunity against rechallenge with SARS-CoV-2, which suggests a role for cellular immunity in the context of waning or subprotective antibody titres. These data demonstrate that relatively low antibody titres are sufficient for protection against SARS-CoV-2 in rhesus macaques, and that cellular immune responses may contribute to protection if antibody responses are suboptimal. We also show that higher antibody titres are required for treatment of SARS-CoV-2 infection in macaques. These findings have implications for the development of SARS-CoV-2 vaccines and immune-based therapeutic agents.
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http://dx.doi.org/10.1038/s41586-020-03041-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906955PMC
February 2021

Epidemiological and immunological features of obesity and SARS-CoV-2.

medRxiv 2020 Dec 11. Epub 2020 Dec 11.

Massachusetts Consortium on Pathogen Readiness, Boston, MA.

Obesity is a key correlate of severe SARS-CoV-2 outcomes while the role of obesity on risk of SARS-CoV-2 infection, symptom phenotype, and immune response are poorly defined. We examined data from a prospective SARS-CoV-2 cohort study to address these questions. Serostatus, body mass index, demographics, comorbidities, and prior COVID-19 compatible symptoms were assessed at baseline and serostatus and symptoms monthly thereafter. SARS-CoV-2 immunoassays included an IgG ELISA targeting the spike RBD, multiarray Luminex targeting 20 viral antigens, pseudovirus neutralization, and T cell ELISPOT assays. Our results from a large prospective SARS-CoV-2 cohort study indicate symptom phenotype is strongly influenced by obesity among younger but not older age groups; we did not identify evidence to suggest obese individuals are at higher risk of SARS-CoV-2 infection; and, remarkably homogenous immune activity across BMI categories suggests natural- and vaccine-induced protection may be similar across these groups.
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http://dx.doi.org/10.1101/2020.11.11.20229724DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7668749PMC
December 2020

Feasibility and safety of ultrasound-guided minimally invasive autopsy in COVID-19 patients.

Abdom Radiol (NY) 2021 03 17;46(3):1263-1271. Epub 2020 Sep 17.

Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

Objectives: To determine the feasibility and safety of ultrasound-guided minimally invasive autopsy in COVID-19 patients.

Methods: 60 patients who expired between 04/22/2020-05/06/2020 due to COVID-19 were considered for inclusion in the study, based on availability of study staff. Minimally invasive ultrasound-guided autopsy was performed with 14G core biopsies through a 13G coaxial needle. The protocol required 20 cores of the liver, 30 of lung, 12 of spleen, 20 of heart, 20 of kidney, 4 of breast, 4 of testis, 2 of skeletal muscle, and 4 of fat with total of 112 cores per patient. Quality of the samples was evaluated by number, size, histology, immunohistochemistry, and in situ hybridization for COVID-19 and PCR-measured viral loads for SARS-CoV-2.

Results: Five (5/60, 8%) patients were included. All approached families gave their consent for the minimally invasive autopsy. All organs for biopsy were successfully targeted with ultrasound guidance obtaining all required samples, apart from 2 patients where renal samples were not obtained due to atrophic kidneys. The number, size, and weight of the tissue cores met expectation of the research group and tissue histology quality was excellent. Pathology findings were concordant with previously reported autopsy findings for COVID-19. Highest SARS-CoV-2 viral load was detected in the lung, liver, and spleen that had small to moderate amount, and low viral load in was detected in the heart in 2/5 (40%). No virus was detected in the kidney (0/3, 0%).

Conclusions: Ultrasound-guided percutaneous post-mortem core biopsies can safely provide adequate tissue. Highest SARS-CoV-2 viral load was seen in the lung, followed by liver and spleen with small amount in the myocardium.
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http://dx.doi.org/10.1007/s00261-020-02753-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7494380PMC
March 2021

Ad26 vaccine protects against SARS-CoV-2 severe clinical disease in hamsters.

Nat Med 2020 11 3;26(11):1694-1700. Epub 2020 Sep 3.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

Coronavirus disease 2019 (COVID-19) in humans is often a clinically mild illness, but some individuals develop severe pneumonia, respiratory failure and death. Studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in hamsters and nonhuman primates have generally reported mild clinical disease, and preclinical SARS-CoV-2 vaccine studies have demonstrated reduction of viral replication in the upper and lower respiratory tracts in nonhuman primates. Here we show that high-dose intranasal SARS-CoV-2 infection in hamsters results in severe clinical disease, including high levels of virus replication in tissues, extensive pneumonia, weight loss and mortality in a subset of animals. A single immunization with an adenovirus serotype 26 vector-based vaccine expressing a stabilized SARS-CoV-2 spike protein elicited binding and neutralizing antibody responses and protected against SARS-CoV-2-induced weight loss, pneumonia and mortality. These data demonstrate vaccine protection against SARS-CoV-2 clinical disease. This model should prove useful for preclinical studies of SARS-CoV-2 vaccines, therapeutics and pathogenesis.
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http://dx.doi.org/10.1038/s41591-020-1070-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7671939PMC
November 2020

Strain-dependent disease and response to favipiravir treatment in mice infected with Chikungunya virus.

Antiviral Res 2020 10 10;182:104904. Epub 2020 Aug 10.

FUJIFILM Toyama Chemical Co., Ltd., Toyama, Japan.

Antiviral countermeasures are needed to reduce the morbidity associated with Chikungunya virus (CHIKV) infection. This arbovirus reemerged in 2004 and causes periodic outbreaks in various areas throughout the world. While infection is rarely lethal, the majority of people infected with the virus develop a hallmark arthralgia as well as other disease manifestations. The virus is classified within three phylogenetic groups, namely, West African, East/Central/South African (ECSA), and Asian. Six strains of CHIKV covering the three phylogenetic groups were studied for their replication in cell culture, their ability to cause disease in susceptible mouse strains and susceptibility to antiviral treatment. Differential replication kinetics were observed for various CHIKV isolates in cell culture, which coincided with a decreased sensitivity to antiviral treatment as compared with ECSA and Asian clade viruses. This was confirmed in mouse infection studies with severe disease observed in mice infected with West African clade viruses, mild disease phenotype after infection with Asian clade viruses and an intermediate disease severity associated with ECSA virus infection. We also tested a broadly active antiviral, Favipiravir (T-705), which activity was inversely proportional to disease severity. These data suggest that some clades of CHIKV may cause more severe disease and may be more difficult to treat.
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http://dx.doi.org/10.1016/j.antiviral.2020.104904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543030PMC
October 2020

Single-shot Ad26 vaccine protects against SARS-CoV-2 in rhesus macaques.

Nature 2020 10 30;586(7830):583-588. Epub 2020 Jul 30.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

A safe and effective vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be required to end the coronavirus disease 2019 (COVID-19) pandemic. For global deployment and pandemic control, a vaccine that requires only a single immunization would be optimal. Here we show the immunogenicity and protective efficacy of a single dose of adenovirus serotype 26 (Ad26) vector-based vaccines expressing the SARS-CoV-2 spike (S) protein in non-human primates. Fifty-two rhesus macaques (Macaca mulatta) were immunized with Ad26 vectors that encoded S variants or sham control, and then challenged with SARS-CoV-2 by the intranasal and intratracheal routes. The optimal Ad26 vaccine induced robust neutralizing antibody responses and provided complete or near-complete protection in bronchoalveolar lavage and nasal swabs after SARS-CoV-2 challenge. Titres of vaccine-elicited neutralizing antibodies correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate robust single-shot vaccine protection against SARS-CoV-2 in non-human primates. The optimal Ad26 vector-based vaccine for SARS-CoV-2, termed Ad26.COV2.S, is currently being evaluated in clinical trials.
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http://dx.doi.org/10.1038/s41586-020-2607-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7581548PMC
October 2020

SARS-CoV-2 infection protects against rechallenge in rhesus macaques.

Science 2020 08 20;369(6505):812-817. Epub 2020 May 20.

Janssen Vaccines & Prevention BV, Leiden, Netherlands.

An understanding of protective immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for vaccine and public health strategies aimed at ending the global coronavirus disease 2019 (COVID-19) pandemic. A key unanswered question is whether infection with SARS-CoV-2 results in protective immunity against reexposure. We developed a rhesus macaque model of SARS-CoV-2 infection and observed that macaques had high viral loads in the upper and lower respiratory tract, humoral and cellular immune responses, and pathologic evidence of viral pneumonia. After the initial viral clearance, animals were rechallenged with SARS-CoV-2 and showed 5 log reductions in median viral loads in bronchoalveolar lavage and nasal mucosa compared with after the primary infection. Anamnestic immune responses after rechallenge suggested that protection was mediated by immunologic control. These data show that SARS-CoV-2 infection induced protective immunity against reexposure in nonhuman primates.
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http://dx.doi.org/10.1126/science.abc4776DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243369PMC
August 2020

DNA vaccine protection against SARS-CoV-2 in rhesus macaques.

Science 2020 08 20;369(6505):806-811. Epub 2020 May 20.

Bioqual, Rockville, MD 20852, USA.

The global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made the development of a vaccine a top biomedical priority. In this study, we developed a series of DNA vaccine candidates expressing different forms of the SARS-CoV-2 spike (S) protein and evaluated them in 35 rhesus macaques. Vaccinated animals developed humoral and cellular immune responses, including neutralizing antibody titers at levels comparable to those found in convalescent humans and macaques infected with SARS-CoV-2. After vaccination, all animals were challenged with SARS-CoV-2, and the vaccine encoding the full-length S protein resulted in >3.1 and >3.7 log reductions in median viral loads in bronchoalveolar lavage and nasal mucosa, respectively, as compared with viral loads in sham controls. Vaccine-elicited neutralizing antibody titers correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate vaccine protection against SARS-CoV-2 in nonhuman primates.
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http://dx.doi.org/10.1126/science.abc6284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243363PMC
August 2020

MYC Controls the Epstein-Barr Virus Lytic Switch.

Mol Cell 2020 05 20;78(4):653-669.e8. Epub 2020 Apr 20.

Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Harvard Graduate Program in Virology, Boston, MA 02115, USA. Electronic address:

Epstein-Barr virus (EBV) is associated with multiple human malignancies. To evade immune detection, EBV switches between latent and lytic programs. How viral latency is maintained in tumors or in memory B cells, the reservoir for lifelong EBV infection, remains incompletely understood. To gain insights, we performed a human genome-wide CRISPR/Cas9 screen in Burkitt lymphoma B cells. Our analyses identified a network of host factors that repress lytic reactivation, centered on the transcription factor MYC, including cohesins, FACT, STAGA, and Mediator. Depletion of MYC or factors important for MYC expression reactivated the lytic cycle, including in Burkitt xenografts. MYC bound the EBV genome origin of lytic replication and suppressed its looping to the lytic cycle initiator BZLF1 promoter. Notably, MYC abundance decreases with plasma cell differentiation, a key lytic reactivation trigger. Our results suggest that EBV senses MYC abundance as a readout of B cell state and highlights Burkitt latency reversal therapeutic targets.
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http://dx.doi.org/10.1016/j.molcel.2020.03.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245572PMC
May 2020

Alpha-defensin 5 differentially modulates adenovirus vaccine vectors from different serotypes in vivo.

PLoS Pathog 2019 12 16;15(12):e1008180. Epub 2019 Dec 16.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston Massachusetts, United States of America.

Adenoviral vectors have shown significant promise as vaccine delivery vectors due to their ability to elicit both innate and adaptive immune responses. α-defensins are effector molecules of the innate immune response and have been shown to modulate natural infection with adenoviruses, but the majority of α-defensin-adenovirus interactions studied to date have only been analyzed in vitro. In this study, we evaluated the role of α-defensin 5 (HD5) in modulating adenovirus vaccine immunogenicity using various serotype adenovirus vectors in mice. We screened a panel of human adenoviruses including Ad5 (species C), Ad26 (species D), Ad35 (species B), Ad48 (species D) and a chimeric Ad5HVR48 for HD5 sensitivity. HD5 inhibited transgene expression from Ad5 and Ad35 but augmented transgene expression from Ad26, Ad48, and Ad5HVR48. HD5 similarly suppressed antigen-specific IgG and CD8+ T cell responses elicited by Ad5 vectors in mice, but augmented IgG and CD8+ T cell responses and innate cytokine responses elicited by Ad26 vectors in mice. Moreover, HD5 suppressed the protective efficacy of Ad5 vectors but enhanced the protective efficacy of Ad26 vectors expressing SIINFEKL against a surrogate Listeria-OVA challenge in mice. These data demonstrate that HD5 differentially modulates adenovirus vaccine delivery vectors in a species-specific manner in vivo.
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http://dx.doi.org/10.1371/journal.ppat.1008180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936886PMC
December 2019

CRISPR-Cas9 Genetic Analysis of Virus-Host Interactions.

Viruses 2018 01 30;10(2). Epub 2018 Jan 30.

Harvard Program in Virology, Harvard Medical School, Boston, MA 02115, USA.

Clustered regularly interspaced short palindromic repeats (CRISPR) has greatly expanded the ability to genetically probe virus-host interactions. CRISPR systems enable focused or systematic, genomewide studies of nearly all aspects of a virus lifecycle. Combined with its relative ease of use and high reproducibility, CRISPR is becoming an essential tool in studies of the host factors important for viral pathogenesis. Here, we review the use of CRISPR-Cas9 for the loss-of-function analysis of host dependency factors. We focus on the use of CRISPR-pooled screens for the systematic identification of host dependency factors, particularly in Epstein-Barr virus-transformed B cells. We also discuss the use of CRISPR interference (CRISPRi) and gain-of-function CRISPR activation (CRISPRa) approaches to probe virus-host interactions. Finally, we comment on the future directions enabled by combinatorial CRISPR screens.
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http://dx.doi.org/10.3390/v10020055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5850362PMC
January 2018

Efficacy of the broad-spectrum antiviral compound BCX4430 against Zika virus in cell culture and in a mouse model.

Antiviral Res 2017 01 10;137:14-22. Epub 2016 Nov 10.

BioCryst Pharmaceuticals Inc., Durham, NC, USA.

Zika virus (ZIKV) is currently undergoing pandemic emergence. While disease is typically subclinical, severe neurologic manifestations in fetuses and newborns after congenital infection underscore an urgent need for antiviral interventions. The adenosine analog BCX4430 has broad-spectrum activity against a wide range of RNA viruses, including potent in vivo activity against yellow fever, Marburg and Ebola viruses. We tested this compound against African and Asian lineage ZIKV in cytopathic effect inhibition and virus yield reduction assays in various cell lines. To further evaluate the efficacy in a relevant animal model, we developed a mouse model of severe ZIKV infection, which recapitulates various human disease manifestations including peripheral virus replication, conjunctivitis, encephalitis and myelitis. Time-course quantification of viral RNA accumulation demonstrated robust viral replication in several relevant tissues, including high and persistent viral loads observed in the brain and testis. The presence of viral RNA in various tissues was confirmed by an infectious culture assay as well as immunohistochemical staining of tissue sections. Treatment of ZIKV-infected mice with BCX4430 significantly improved outcome even when treatment was initiated during the peak of viremia. The demonstration of potent activity of BCX4430 against ZIKV in a lethal mouse model warrant its continued clinical development.
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http://dx.doi.org/10.1016/j.antiviral.2016.11.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5215849PMC
January 2017

Serum amyloid A (SAA) is an early biomarker of influenza virus disease in BALB/c, C57BL/2, Swiss-Webster, and DBA.2 mice.

Antiviral Res 2016 09 11;133:196-207. Epub 2016 Aug 11.

Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, USA.

Assessment of influenza virus disease progression and efficacy of antiviral therapy in the widely used mouse models relies mostly on body weight loss and lung virus titers as markers of disease. However, both parameters have their shortcomings. Therefore, the aim of our study was to find non-invasive markers in the murine model of severe influenza that could detect disease early and predict disease outcome. BALB/c mice were lethally infected with influenza A(H1N1)pdm09 virus and serum samples were collected at various time points. Enzyme-linked immunosorbent assays were performed to quantify amounts of serum amyloid A (SAA), C-reactive protein, complement 3, transferrin, corticosterone, prostaglandin E2, H2O2, and alpha-2,6-sialyltransferase. We found that SAA was the most promising candidate with levels acutely and temporarily elevated by several hundred-fold 3 days post virus inoculation. Upon treatment with oseltamivir phosphate, levels of SAA were significantly decreased. High levels of SAA were associated with poor disease prognosis, whereas body weight loss was not as a reliable predictor of disease outcome. SAA levels were also transiently increased in BALB/c mice infected with influenza A(H3N2) and influenza B virus, as well as in C57BL/2, Swiss-Webster, and DBA.2 mice infected with influenza A(H1N1)pdm09 virus. High levels of SAA often, but not always, were associated with disease outcome in these other influenza virus mouse models. Therefore, SAA represents a valid biomarker for influenza disease detection in all tested mouse strains but its prognostic value is limited to BALB/c mice infected with influenza A(H1N1)pdm09 virus.
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http://dx.doi.org/10.1016/j.antiviral.2016.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042138PMC
September 2016
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