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Sun Z, Chen C, Li W, Martinez DR, Drelich A, Baek DS, Liu X, Mellors JW, Tseng CT, Baric RS, Dimitrov DS. Potent neutralization of SARS-CoV-2 by human antibody heavy-chain variable domains isolated from a large library with a new stable scaffold. MAbs 2020; 12:1778435. [PMID: 32544372 PMCID: PMC7531518 DOI: 10.1080/19420862.2020.1778435] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Effective therapies are urgently needed for COVID-19. Here we describe the identification of a new stable human immunoglobulin G1 heavy-chain variable (VH) domain scaffold that was used for the construction of a large library, lCAT6, of engineered human VHs. This library was panned against the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) glycoprotein. Two VH domains (VH ab6 and VH m397) were selected and fused to Fc for increased half-life in circulation. The VH-Fc ab6 and m397 specifically neutralized SARS-CoV-2 with high potencies (50% neutralization at 0.35 µg/ml and 1.5 µg/ml, respectively) as measured by two independent replication-competent virus neutralization assays. Ab6 and m397 competed with ACE2 for binding to RBD, suggesting a competitive mechanism of virus neutralization. These VH domains may have potential applications for prophylaxis and therapy of COVID-19 alone or in combination, as well as for diagnosis and as tools for research.
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Corbett KS, Edwards D, Leist SR, Abiona OM, Boyoglu-Barnum S, Gillespie RA, Himansu S, Schäfer A, Ziwawo CT, DiPiazza AT, Dinnon KH, Elbashir SM, Shaw CA, Woods A, Fritch EJ, Martinez DR, Bock KW, Minai M, Nagata BM, Hutchinson GB, Bahl K, Garcia-Dominguez D, Ma L, Renzi I, Kong WP, Schmidt SD, Wang L, Zhang Y, Stevens LJ, Phung E, Chang LA, Loomis RJ, Altaras NE, Narayanan E, Metkar M, Presnyak V, Liu C, Louder MK, Shi W, Leung K, Yang ES, West A, Gully KL, Wang N, Wrapp D, Doria-Rose NA, Stewart-Jones G, Bennett H, Nason MC, Ruckwardt TJ, McLellan JS, Denison MR, Chappell JD, Moore IN, Morabito KM, Mascola JR, Baric RS, Carfi A, Graham BS. SARS-CoV-2 mRNA Vaccine Development Enabled by Prototype Pathogen Preparedness. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.06.11.145920. [PMID: 32577634 PMCID: PMC7301911 DOI: 10.1101/2020.06.11.145920] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A SARS-CoV-2 vaccine is needed to control the global COVID-19 public health crisis. Atomic-level structures directed the application of prefusion-stabilizing mutations that improved expression and immunogenicity of betacoronavirus spike proteins. Using this established immunogen design, the release of SARS-CoV-2 sequences triggered immediate rapid manufacturing of an mRNA vaccine expressing the prefusion-stabilized SARS-CoV-2 spike trimer (mRNA-1273). Here, we show that mRNA-1273 induces both potent neutralizing antibody and CD8 T cell responses and protects against SARS-CoV-2 infection in lungs and noses of mice without evidence of immunopathology. mRNA-1273 is currently in a Phase 2 clinical trial with a trajectory towards Phase 3 efficacy evaluation.
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Li W, Drelich A, Martinez DR, Gralinski L, Chen C, Sun Z, Schäfer A, Leist SR, Liu X, Zhelev D, Zhang L, Peterson EC, Conard A, Mellors JW, Tseng CT, Baric RS, Dimitrov DS. Rapid selection of a human monoclonal antibody that potently neutralizes SARS-CoV-2 in two animal models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511413 DOI: 10.1101/2020.05.13.093088] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Effective therapies are urgently needed for the SARS-CoV-2/COVID19 pandemic. We identified panels of fully human monoclonal antibodies (mAbs) from eight large phage-displayed Fab, scFv and VH libraries by panning against the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) glycoprotein. One high affinity mAb, IgG1 ab1, specifically neutralized replication competent SARS-CoV-2 with exceptional potency as measured by two different assays. There was no enhancement of pseudovirus infection in cells expressing Fcγ receptors at any concentration. It competed with human angiotensin-converting enzyme 2 (hACE2) for binding to RBD suggesting a competitive mechanism of virus neutralization. IgG1 ab1 potently neutralized mouse ACE2 adapted SARS-CoV-2 in wild type BALB/c mice and native virus in hACE2 expressing transgenic mice. The ab1 sequence has relatively low number of somatic mutations indicating that ab1-like antibodies could be quickly elicited during natural SARS-CoV-2 infection or by RBD-based vaccines. IgG1 ab1 does not have developability liabilities, and thus has potential for therapy and prophylaxis of SARS-CoV-2 infections. The rapid identification (within 6 days) of potent mAbs shows the value of large antibody libraries for response to public health threats from emerging microbes.
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Post AL, Li SH, Berry M, Itell H, Martinez DR, Xie G, Permar SR, Swamy GK, Fouda GG. Efficiency of placental transfer of vaccine-elicited antibodies relative to prenatal Tdap vaccination status. Vaccine 2020; 38:4869-4876. [PMID: 32482459 DOI: 10.1016/j.vaccine.2020.05.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 03/19/2020] [Accepted: 05/13/2020] [Indexed: 12/27/2022]
Abstract
Administration of vaccines during pregnancy provides maternal protection against infectious diseases. This protection is extended to their infants during the first months of life, as pathogen-specific antibodies formed in response to maternal vaccination are transferred across the placenta to the fetus. Notably, Tdap (tetanus-diphtheria-acellular pertussis) vaccination booster is routinely administered to pregnant women both to prevent neonatal tetanus and to ensure that infants have protective levels of pertussis antibodies until they are able to establish their own vaccine-induced levels. Whether infant protection through maternal immunization is merely due to an increase in maternal antibody levels or whether maternal immunization enhances the transfer of vaccine-specific antibodies is unclear. Moreover, the potential impact of prenatal vaccinations on the transplacental transfer of other antibodies, such as antibodies raised as a result of infections or other vaccines administered prior to pregnancy, has not been studied. The goal of this study was to define the impact of maternal vaccination on IgG transplacental transfer efficiency. We analyzed antigen-specific antibody populations and IgG subclass distribution in maternal and cord blood samples from 58 mother-infant pairs. All women received the seasonal inactivated influenza vaccine during pregnancy and 25 women received the Tdap vaccine during the second or third trimester of gestation. Prenatal Tdap vaccination did not impact the efficiency of IgG transplacental transfer; however, it was associated with higher maternal and infant vaccine-elicited Tdap-specific antibody levels, and with a higher proportion of infants with protective levels of antibodies, especially against diphtheria. There was also no difference in the IgG transplacental transfer rate of antibodies against non-Tdap vaccines between the two groups of women. Our results confirm previous reports demonstrating the benefits of prenatal Tdap immunization and indicate that this strategy does not impede the transplacental transfer of other antibodies that are also important for infant protection.
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Zost SJ, Gilchuk P, Case JB, Binshtein E, Chen RE, Reidy JX, Trivette A, Nargi RS, Sutton RE, Suryadevara N, Williamson LE, Chen EC, Jones T, Day S, Myers L, Hassan AO, Kafai NM, Winkler ES, Fox JM, Steinhardt JJ, Ren K, Loo YM, Kallewaard NL, Martinez DR, Schäfer A, Gralinski LE, Baric RS, Thackray LB, Diamond MS, Carnahan RH, Crowe JE. Potently neutralizing human antibodies that block SARS-CoV-2 receptor binding and protect animals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511409 DOI: 10.1101/2020.05.22.111005] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The COVID-19 pandemic is a major threat to global health for which there are only limited medical countermeasures, and we lack a thorough understanding of mechanisms of humoral immunity 1,2 . From a panel of monoclonal antibodies (mAbs) targeting the spike (S) glycoprotein isolated from the B cells of infected subjects, we identified several mAbs that exhibited potent neutralizing activity with IC 50 values as low as 0.9 or 15 ng/mL in pseudovirus or wild-type ( wt ) SARS-CoV-2 neutralization tests, respectively. The most potent mAbs fully block the receptor-binding domain of S (S RBD ) from interacting with human ACE2. Competition-binding, structural, and functional studies allowed clustering of the mAbs into defined classes recognizing distinct epitopes within major antigenic sites on the S RBD . Electron microscopy studies revealed that these mAbs recognize distinct conformational states of trimeric S protein. Potent neutralizing mAbs recognizing unique sites, COV2-2196 and COV2-2130, bound simultaneously to S and synergistically neutralized authentic SARS-CoV-2 virus. In two murine models of SARS-CoV-2 infection, passive transfer of either COV2-2916 or COV2-2130 alone or a combination of both mAbs protected mice from severe weight loss and reduced viral burden and inflammation in the lung. These results identify protective epitopes on the S RBD and provide a structure-based framework for rational vaccine design and the selection of robust immunotherapeutic cocktails.
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Chandrashekar A, Liu J, Martinot AJ, McMahan K, Mercado NB, Peter L, Tostanoski LH, Yu J, Maliga Z, Nekorchuk M, Busman-Sahay K, Terry M, Wrijil LM, Ducat S, Martinez DR, Atyeo C, Fischinger S, Burke JS, Slein MD, Pessaint L, Van Ry A, Greenhouse J, Taylor T, Blade K, Cook A, Finneyfrock B, Brown R, Teow E, Velasco J, Zahn R, Wegmann F, Abbink P, Bondzie EA, Dagotto G, Gebre MS, He X, Jacob-Dolan C, Kordana N, Li Z, Lifton MA, Mahrokhian SH, Maxfield LF, Nityanandam R, Nkolola JP, Schmidt AG, Miller AD, Baric RS, Alter G, Sorger PK, Estes JD, Andersen H, Lewis MG, Barouch DH. SARS-CoV-2 infection protects against rechallenge in rhesus macaques. Science 2020; 369:812-817. [PMID: 32434946 PMCID: PMC7243369 DOI: 10.1126/science.abc4776] [Citation(s) in RCA: 650] [Impact Index Per Article: 162.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 05/16/2020] [Indexed: 12/13/2022]
Abstract
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 log10 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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Zost SJ, Gilchuk P, Chen RE, Case JB, Reidy JX, Trivette A, Nargi RS, Sutton RE, Suryadevara N, Chen EC, Binshtein E, Shrihari S, Ostrowski M, Chu HY, Didier JE, MacRenaris KW, Jones T, Day S, Myers L, Lee FEH, Nguyen DC, Sanz I, Martinez DR, Baric RS, Thackray LB, Diamond MS, Carnahan RH, Crowe JE. Rapid isolation and profiling of a diverse panel of human monoclonal antibodies targeting the SARS-CoV-2 spike protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511414 DOI: 10.1101/2020.05.12.091462] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antibodies are a principal determinant of immunity for most RNA viruses and have promise to reduce infection or disease during major epidemics. The novel coronavirus SARS-CoV-2 has caused a global pandemic with millions of infections and hundreds of thousands of deaths to date 1,2 . In response, we used a rapid antibody discovery platform to isolate hundreds of human monoclonal antibodies (mAbs) against the SARS-CoV-2 spike (S) protein. We stratify these mAbs into five major classes based on their reactivity to subdomains of S protein as well as their cross-reactivity to SARS-CoV. Many of these mAbs inhibit infection of authentic SARS-CoV-2 virus, with most neutralizing mAbs recognizing the receptor-binding domain (RBD) of S. This work defines sites of vulnerability on SARS-CoV-2 S and demonstrates the speed and robustness of new antibody discovery methodologies.
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Premkumar L, Segovia-Chumbez B, Jadi R, Martinez DR, Raut R, Markmann A, Cornaby C, Bartelt L, Weiss S, Park Y, Edwards CE, Weimer E, Scherer EM, Roupael N, Edupuganti S, Weiskopf D, Tse LV, Hou YJ, Margolis D, Sette A, Collins MH, Schmitz J, Baric RS, de Silva AM. The RBD Of The Spike Protein Of SARS-Group Coronaviruses Is A Highly Specific Target Of SARS-CoV-2 Antibodies But Not Other Pathogenic Human and Animal Coronavirus Antibodies. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2020. [PMID: 32511572 DOI: 10.1101/2020.05.06.20093377] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A new Severe Acute Respiratory Syndrome Coronavirus variant (SARS-CoV-2) that first emerged in late 2019 is responsible for a pandemic of severe respiratory illness. People infected with this highly contagious virus present with clinically inapparent, mild or severe disease. Currently, the presence of the virus in individual patients and at the population level is being monitored by testing symptomatic cases by PCR for the presence of viral RNA. There is an urgent need for SARS-CoV-2 serologic tests to identify all infected individuals, irrespective of clinical symptoms, to conduct surveillance and implement strategies to contain spread. As the receptor binding domain (RBD) of the viral spike (S) protein is poorly conserved between SARS-CoVs and other pathogenic human coronaviruses, the RBD represents a promising antigen for detecting CoV specific antibodies in people. Here we use a large panel of human sera (70 SARS-CoV-2 patients and 71 control subjects) and hyperimmune sera from animals exposed to zoonotic CoVs to evaluate the performance of the RBD as an antigen for accurate detection of SARS-CoV-2-specific antibodies. By day 9 after the onset of symptoms, the recombinant SARS-CoV-2 RBD antigen was highly sensitive (98%) and specific (100%) to antibodies induced by SARS-CoVs. We observed a robust correlation between levels of RBD binding antibodies and SARS-CoV-2 neutralizing antibodies in patients. Our results, which reveal the early kinetics of SARS-CoV-2 antibody responses, strongly support the use of RBD-based antibody assays for population-level surveillance and as a correlate of neutralizing antibody levels in people who have recovered from SARS-CoV-2 infections.
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Dinnon KH, Leist SR, Schäfer A, Edwards CE, Martinez DR, Montgomery SA, West A, Yount BL, Hou YJ, Adams LE, Gully KL, Brown AJ, Huang E, Bryant MD, Choong IC, Glenn JS, Gralinski LE, Sheahan TP, Baric RS. A mouse-adapted SARS-CoV-2 model for the evaluation of COVID-19 medical countermeasures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.05.06.081497. [PMID: 32511406 PMCID: PMC7263553 DOI: 10.1101/2020.05.06.081497] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Coronaviruses are prone to emergence into new host species most recently evidenced by SARS-CoV-2, the causative agent of the COVID-19 pandemic. Small animal models that recapitulate SARS-CoV-2 disease are desperately needed to rapidly evaluate medical countermeasures (MCMs). SARS-CoV-2 cannot infect wildtype laboratory mice due to inefficient interactions between the viral spike (S) protein and the murine ortholog of the human receptor, ACE2. We used reverse genetics to remodel the S and mACE2 binding interface resulting in a recombinant virus (SARS-CoV-2 MA) that could utilize mACE2 for entry. SARS-CoV-2 MA replicated in both the upper and lower airways of both young adult and aged BALB/c mice. Importantly, disease was more severe in aged mice, and showed more clinically relevant phenotypes than those seen in hACE2 transgenic mice. We then demonstrated the utility of this model through vaccine challenge studies in immune competent mice with native expression of mACE2. Lastly, we show that clinical candidate interferon (IFN) lambda-1a can potently inhibit SARS-CoV-2 replication in primary human airway epithelial cells in vitro , and both prophylactic and therapeutic administration diminished replication in mice. Our mouse-adapted SARS-CoV-2 model demonstrates age-related disease pathogenesis and supports the clinical use of IFN lambda-1a treatment in human COVID-19 infections.
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Pruijssers AJ, George AS, Schäfer A, Leist SR, Gralinksi LE, Dinnon KH, Yount BL, Agostini ML, Stevens LJ, Chappell JD, Lu X, Hughes TM, Gully K, Martinez DR, Brown AJ, Graham RL, Perry JK, Du Pont V, Pitts J, Ma B, Babusis D, Murakami E, Feng JY, Bilello JP, Porter DP, Cihlar T, Baric RS, Denison MR, Sheahan TP. Remdesivir potently inhibits SARS-CoV-2 in human lung cells and chimeric SARS-CoV expressing the SARS-CoV-2 RNA polymerase in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511392 DOI: 10.1101/2020.04.27.064279] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 as the causative agent of the novel pandemic viral disease COVID-19. With no approved therapies, this pandemic illustrates the urgent need for safe, broad-spectrum antiviral countermeasures against SARS-CoV-2 and future emerging CoVs. We report that remdesivir (RDV), a monophosphoramidate prodrug of an adenosine analog, potently inhibits SARS-CoV-2 replication in human lung cells and primary human airway epithelial cultures (EC 50 = 0.01 μM). Weaker activity was observed in Vero E6 cells (EC 50 = 1.65 μM) due to their low capacity to metabolize RDV. To rapidly evaluate in vivo efficacy, we engineered a chimeric SARS-CoV encoding the viral target of RDV, the RNA-dependent RNA polymerase, of SARS-CoV-2. In mice infected with chimeric virus, therapeutic RDV administration diminished lung viral load and improved pulmonary function as compared to vehicle treated animals. These data provide evidence that RDV is potently active against SARS-CoV-2 in vitro and in vivo , supporting its further clinical testing for treatment of COVID-19.
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Langel SN, Otero CE, Martinez DR, Permar SR. Maternal gatekeepers: How maternal antibody Fc characteristics influence passive transfer and infant protection. PLoS Pathog 2020; 16:e1008303. [PMID: 32214394 PMCID: PMC7098569 DOI: 10.1371/journal.ppat.1008303] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Martinez DR, Tu JJ, Kumar A, Mangold JF, Mangan RJ, Goswami R, Giorgi EE, Chen J, Mengual M, Douglas AO, Heimsath H, Saunders KO, Nicely NI, Eudailey J, Hernandez G, Morgan-Asiedu PK, Wiehe K, Haynes BF, Moody MA, LaBranche C, Montefiori DC, Gao F, Permar SR. Maternal Broadly Neutralizing Antibodies Can Select for Neutralization-Resistant, Infant-Transmitted/Founder HIV Variants. mBio 2020; 11:e00176-20. [PMID: 32156815 PMCID: PMC7064758 DOI: 10.1128/mbio.00176-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 01/21/2023] Open
Abstract
Each year, >180,000 infants become infected via mother-to-child transmission (MTCT) of HIV despite the availability of effective maternal antiretroviral treatments, underlining the need for a maternal HIV vaccine. We characterized 224 maternal HIV envelope (Env)-specific IgG monoclonal antibodies (MAbs) from seven nontransmitting and transmitting HIV-infected U.S. and Malawian mothers and examined their neutralization activities against nontransmitted autologous circulating viruses and infant-transmitted founder (infant-T/F) viruses. Only a small subset of maternal viruses, 3 of 72 (4%), were weakly neutralized by maternal linear V3 epitope-specific IgG MAbs, whereas 6 out of 6 (100%) infant-T/F viruses were neutralization resistant to these V3-specific IgG MAbs. We also show that maternal-plasma broadly neutralizing antibody (bNAb) responses targeting the V3 glycan supersite in a transmitting woman may have selected for an N332 V3 glycan neutralization-resistant infant-T/F virus. These data have important implications for bNAb-eliciting vaccines and passively administered bNAbs in the setting of MTCT.IMPORTANCE Efforts to eliminate MTCT of HIV with antiretroviral therapy (ART) have met little success, with >180,000 infant infections each year worldwide. It is therefore likely that additional immunologic strategies that can synergize with ART will be required to eliminate MTCT of HIV. To this end, understanding the role of maternal HIV Env-specific IgG antibodies in the setting of MTCT is crucial. In this study, we found that maternal-plasma broadly neutralizing antibody (bNAb) responses can select for T/F viruses that initiate infection in infants. We propose that clinical trials testing the efficacy of single bNAb specificities should not include HIV-infected pregnant women, as a single bNAb might select for neutralization-resistant infant-T/F viruses.
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88
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Martinez DR, Fong Y, Li SH, Yang F, Jennewein MF, Weiner JA, Harrell EA, Mangold JF, Goswami R, Seage GR, Alter G, Ackerman ME, Peng X, Fouda GG, Permar SR. Fc Characteristics Mediate Selective Placental Transfer of IgG in HIV-Infected Women. Cell 2019; 178:190-201.e11. [PMID: 31204101 DOI: 10.1016/j.cell.2019.05.046] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/11/2019] [Accepted: 05/22/2019] [Indexed: 10/26/2022]
Abstract
The placental transfer of maternal IgG is critical for infant protection against infectious pathogens. However, factors that modulate the placental transfer of IgG remain largely undefined. HIV-infected women have impaired placental IgG transfer, presenting a unique "disruption model" to define factors that modulate placental IgG transfer. We measured the placental transfer efficiency of maternal HIV and pathogen-specific IgG in US and Malawian HIV-infected mothers and their HIV-exposed uninfected and infected infants. We examined the role of maternal HIV disease progression, infant factors, placental Fc receptor expression, IgG subclass, and glycan signatures and their association with placental IgG transfer efficiency. Maternal IgG characteristics, such as binding to placentally expressed Fc receptors FcγRIIa and FcγRIIIa, and Fc region glycan profiles were associated with placental IgG transfer efficiency. Our findings suggest that Fc region characteristics modulate the selective placental transfer of IgG, with implications for maternal vaccine design and infant health.
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Martinez DR, Fouda GG, Peng X, Ackerman ME, Permar SR. Noncanonical placental Fc receptors: What is their role in modulating transplacental transfer of maternal IgG? PLoS Pathog 2018; 14:e1007161. [PMID: 30161231 PMCID: PMC6117057 DOI: 10.1371/journal.ppat.1007161] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Kumar A, Smith CEP, Giorgi EE, Eudailey J, Martinez DR, Yusim K, Douglas AO, Stamper L, McGuire E, LaBranche CC, Montefiori DC, Fouda GG, Gao F, Permar SR. Infant transmitted/founder HIV-1 viruses from peripartum transmission are neutralization resistant to paired maternal plasma. PLoS Pathog 2018; 14:e1006944. [PMID: 29672607 PMCID: PMC5908066 DOI: 10.1371/journal.ppat.1006944] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/16/2018] [Indexed: 01/17/2023] Open
Abstract
Despite extensive genetic diversity of HIV-1 in chronic infection, a single or few maternal virus variants become the founders of an infant’s infection. These transmitted/founder (T/F) variants are of particular interest, as a maternal or infant HIV vaccine should raise envelope (Env) specific IgG responses capable of blocking this group of viruses. However, the maternal or infant factors that contribute to selection of infant T/F viruses are not well understood. In this study, we amplified HIV-1 env genes by single genome amplification from 16 mother-infant transmitting pairs from the U.S. pre-antiretroviral era Women Infant Transmission Study (WITS). Infant T/F and representative maternal non-transmitted Env variants from plasma were identified and used to generate pseudoviruses for paired maternal plasma neutralization sensitivity analysis. Eighteen out of 21 (85%) infant T/F Env pseudoviruses were neutralization resistant to paired maternal plasma. Yet, all infant T/F viruses were neutralization sensitive to a panel of HIV-1 broadly neutralizing antibodies and variably sensitive to heterologous plasma neutralizing antibodies. Also, these infant T/F pseudoviruses were overall more neutralization resistant to paired maternal plasma in comparison to pseudoviruses from maternal non-transmitted variants (p = 0.012). Altogether, our findings suggest that autologous neutralization of circulating viruses by maternal plasma antibodies select for neutralization-resistant viruses that initiate peripartum transmission, raising the speculation that enhancement of this response at the end of pregnancy could further reduce infant HIV-1 infection risk. Mother to child transmission (MTCT) of HIV-1 can occur during pregnancy (in utero), at the time of delivery (peripartum) or by breastfeeding (postpartum). With the availability of anti-retroviral therapy (ART), rate of MTCT of HIV-1 have been significantly lowered. However, significant implementation challenges remain in resource-poor areas, making it difficult to eliminate pediatric HIV. An improved understanding of the viral population (escape variants from autologous neutralizing antibodies) that lead to infection of infants at time of transmission will help in designing immune interventions to reduce perinatal HIV-1 transmission. Here, we selected 16 HIV-1-infected mother-infant pairs from WITS cohort (from pre anti-retroviral era), where infants became infected peripartum. HIV-1 env gene sequences were obtained by the single genome amplification (SGA) method. The sensitivity of these infant Env pseudoviruses against paired maternal plasma and a panel of broadly neutralizing monoclonal antibodies (bNAbs) was analyzed. We demonstrated that the infant T/F viruses were more resistant against maternal plasma than non-transmitted maternal variants, but sensitive to most (bNAbs). Signature sequence analysis of infant T/F and non-transmitted maternal variants revealed the potential importance of V3 and MPER region for resistance against paired maternal plasma. These findings provide insights for the design of maternal immunization strategies to enhance neutralizing antibodies that target V3 region of autologous virus populations, which could work synergistically with maternal ARVs to further reduce the rate of peripartum HIV-1 transmission.
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91
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Nguyen QN, Martinez DR, Himes JE, Whitney Edwards R, Han Q, Kumar A, Mangan R, Nicely NI, Xie G, Vandergrift N, Shen X, Pollara J, Permar SR. Predominant envelope variable loop 2-specific and gp120-specific antibody-dependent cellular cytotoxicity antibody responses in acutely SIV-infected African green monkeys. Retrovirology 2018. [PMID: 29523166 PMCID: PMC5845189 DOI: 10.1186/s12977-018-0406-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background The initial envelope (Env)-specific antibody response in acutely HIV-1-infected individuals and simian immunodeficiency virus (SIV)-infected rhesus monkeys (RMs) is dominated by non-neutralizing antibodies targeting Env gp41. In contrast, natural primate SIV hosts, such as African green monkeys (AGMs), develop a predominant Env gp120-specific antibody response to SIV infection. However, the fine-epitope specificity and function of SIV Env-specific plasma IgG, and their potential role on autologous virus co-evolution in SIV-infected AGMs and RMs remain unclear. Results Unlike the dominant linear gp41-specific IgG responses in RMs, SIV-infected AGMs demonstrated a unique linear variable loop 2 (V2)-specific plasma IgG response that arose concurrently with high gp120-directed antibody-dependent cellular cytotoxicity (ADCC) activity, and SIVsab-infected cell binding responses during acute infection. Moreover, SIV variants isolated from SIV-infected AGMs exhibited high amino acid mutation frequencies within the Env V1V2 loop compared to those of RMs. Notably, the linear V2-specific IgG epitope in AGMs overlaps with an analogous region of the HIV V2 loop containing the K169 mutation epitope identified in breakthrough viruses from RV144 vaccinees. Conclusion Vaccine-elicited Env V2-specific IgG responses have been proposed as an immune correlate of reduced risk in HIV-1/SIV acquisition in humans and RMs. Yet the pathways to elicit these potentially-protective V2-specific IgG responses remain unclear. In this study, we demonstrate that SIV-infected AGMs, which are the natural hosts of SIV, exhibited high plasma linear V2-specific IgG binding responses that arose concurrently with SIV Env gp120-directed ADCC-mediating, and SIV-infected cell plasma IgG binding responses during acute SIV infection, which were not present in acutely SIV-infected RMs. The linear V2-specific antibody response in AGMs targets an overlapping epitope of the proposed site of vaccine-induced immune pressure defined in the moderately protective RV144 HIV-1 vaccine trial. Identifying host factors that control the early elicitation of Env V2-specific IgG and ADCC antibody responses in these natural SIV hosts could inform vaccination strategies aimed at rapidly inducing potentially-protective HIV-1 Env-specific responses in humans. Electronic supplementary material The online version of this article (10.1186/s12977-018-0406-5) contains supplementary material, which is available to authorized users.
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Fouda GG, Martinez DR, Swamy GK, Permar SR. The Impact of IgG transplacental transfer on early life immunity. Immunohorizons 2018; 2:14-25. [PMID: 29457151 PMCID: PMC5812294 DOI: 10.4049/immunohorizons.1700057] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Pediatric vaccines have significantly reduced infectious disease-related infant mortality, but as protective immunity often require several infant vaccine doses; maternally-acquired antibodies are critical to protect infants during the first months of life. Consequently, immunization of pregnant women is an important strategy not only to protect mothers from infection, but also to provide immunity to young infants. Nevertheless, maternal immunization can also negatively impact early life immunity. In fact, maternal antibodies can interfere with the development of infant immune responses, though it is unclear if such interference is clinically significant. Moreover, the transplacental transfer of maternal immunoglobulin therapeutics can be harmful to the fetus. Thus, the risk/benefit of maternal immunization for both the mother and the fetus should be carefully weighed. In addition, it is critical to fully understand the mechanisms by which IgG is transferred across the placenta in order to develop optimal maternal and infant immunization strategies.
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Itell HL, Nelson CS, Martinez DR, Permar SR. Maternal immune correlates of protection against placental transmission of cytomegalovirus. Placenta 2017; 60 Suppl 1:S73-S79. [PMID: 28456432 PMCID: PMC5650553 DOI: 10.1016/j.placenta.2017.04.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 04/07/2017] [Accepted: 04/13/2017] [Indexed: 02/02/2023]
Abstract
Human cytomegalovirus (HCMV) is the most common congenitally transmitted pathogen worldwide, impacting an estimated 1 million newborns annually. In a subset of infected infants, congenital HCMV causes severe, long-lasting sequelae, including deafness, microcephaly, neurodevelopmental delay, and even death. Accordingly, a maternal vaccine to prevent congenital HCMV infection continues to be a top public health priority. Nevertheless, all vaccines tested to date have failed to meet clinical trial endpoints. Maternal immunity provides partial protection against congenital HCMV transmission, as vertical transmission from seropositive mothers is relatively rare. Therefore, an understanding of the maternal immune correlates of protection against HCMV congenital infection will be critical to inform design of an efficacious maternal vaccine. This review summarizes our understanding of the innate and adaptive immune correlates of protection against congenital transmission of HCMV, and discusses the advantages and applications of a novel nonhuman primate model of congenital CMV transmission to aid in rational vaccine design and evaluation.
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Anderson M, Barták R, Brownstein JS, Buckeridge DL, Eldardiry H, Geib C, Gini M, Isaksen A, Keren S, Laddaga R, Lisy V, Martin R, Martinez DR, Michalowski M, Michael L, Mirsky R, Nguyen T, Paul MJ, Pontelli E, Sanner S, Shaban-Nejad A, Sinha A, Sohrabi S, Sricharan K, Srivastava B, Stefik M, Streilein WW, Sturtevant N, Talamadupula K, Thielscher M, Togelius J, Tran SC, Tran-Thanh L, Wagner N, Wallace BC, Wilk S, Zhu J. Reports of the Workshops of the Thirty-First AAAI Conference on Artificial Intelligence. AI MAG 2017. [DOI: 10.1609/aimag.v38i3.2755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The AAAI-17 workshop program included 17 workshops covering a wide range of topics in AI. Workshops were held Sunday and Monday, February 4-5, 2017 at the Hilton San Francisco Union Square in San Francisco, California, USA. This report contains summaries of 12 of the workshops, and brief abstracts of the remaining 5
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Douglas AO, Martinez DR, Permar SR. The Role of Maternal HIV Envelope-Specific Antibodies and Mother-to-Child Transmission Risk. Front Immunol 2017; 8:1091. [PMID: 28928750 PMCID: PMC5591431 DOI: 10.3389/fimmu.2017.01091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/21/2017] [Indexed: 11/13/2022] Open
Abstract
Despite the wide availability of antiretroviral therapy (ART) prophylaxis during pregnancy, >150,000 infants become infected through mother-to-child transmission (MTCT) of HIV worldwide. It is likely that additional intervention strategies, such as a maternal HIV vaccine, will be required to eliminate pediatric HIV infections. A deeper understanding of the fine specificity and function of maternal HIV envelope (Env)-specific responses that provide partial protection against MTCT will be critical to inform the design of immunologic strategies to curb the pediatric HIV epidemic. Recent studies have underlined a role of maternal HIV Env-specific neutralizing and non-neutralizing responses in reducing risk of MTCT of HIV and in prolonging survival rates in HIV-infected infants. However, critical gaps in our knowledge include (A) the specific role of maternal autologous-virus IgG-neutralizing responses in driving the selection of infant transmitted founder (T/F) viruses and (B) Env mechanisms of escape from maternal autologous virus-neutralizing antibodies (NAbs). A more refined understanding of the fine specificities of maternal autologous virus NAbs and ways that maternal circulating viruses escape from these antibodies will be crucial to inform maternal vaccination strategies that can block MTCT to help achieve an HIV-free generation.
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Perez LG, Martinez DR, deCamp AC, Pinter A, Berman PW, Francis D, Sinangil F, Lee C, Greene K, Gao H, Nitayaphan S, Rerks-Ngarm S, Kaewkungwal J, Pitisuttithum P, Tartaglia J, O’Connell RJ, Robb ML, Michael NL, Kim JH, Gilbert P, Montefiori DC. V1V2-specific complement activating serum IgG as a correlate of reduced HIV-1 infection risk in RV144. PLoS One 2017; 12:e0180720. [PMID: 28678869 PMCID: PMC5498072 DOI: 10.1371/journal.pone.0180720] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 06/20/2017] [Indexed: 12/18/2022] Open
Abstract
Non-neutralizing IgG to the V1V2 loop of HIV-1 gp120 correlates with a decreased risk of HIV-1 infection but the mechanism of protection remains unknown. This V1V2 IgG correlate was identified in RV144 Thai trial vaccine recipients, who were primed with a canarypox vector expressing membrane-bound gp120 (vCP1521) and boosted with vCP1521 plus a mixture gp120 proteins from clade B and clade CRF01_AE (B/E gp120). We sought to determine whether the mechanism of vaccine protection might involve antibody-dependent complement activation. Complement activation was measured as a function of complement component C3d deposition on V1V2-coated beads in the presence of RV144 sera. Variable levels of complement activation were detected two weeks post final boosting in RV144, which is when the V1V2 IgG correlate was identified. The magnitude of complement activation correlated with V1V2-specific serum IgG and was stronger and more common in RV144 than in HIV-1 infected individuals and two related HIV-1 vaccine trials, VAX003 and VAX004, where no protection was seen. After adjusting for gp120 IgA, V1V2 IgG, gender, and risk score, complement activation by case-control plasmas from RV144 correlated inversely with a reduced risk of HIV-1 infection, with odds ratio for positive versus negative response to TH023-V1V2 0.42 (95% CI 0.18 to 0.99, p = 0.048) and to A244-V1V2 0.49 (95% CI 0.21 to 1.10, p = 0.085). These results suggest that complement activity may have contributed in part to modest protection against the acquisition of HIV-1 infection seen in the RV144 trial.
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Martinez DR, Jaksic FM. Habitat, relative abundance, and diet of rufous-legged owls (Strix rufipesKing) in temperate forest remnants of southern Chile. ECOSCIENCE 2016. [DOI: 10.1080/11956860.1996.11682340] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Permar SR, Fong Y, Vandergrift N, Fouda GG, Gilbert P, Parks R, Jaeger FH, Pollara J, Martelli A, Liebl BE, Lloyd K, Yates NL, Overman RG, Shen X, Whitaker K, Chen H, Pritchett J, Solomon E, Friberg E, Marshall DJ, Whitesides JF, Gurley TC, Von Holle T, Martinez DR, Cai F, Kumar A, Xia SM, Lu X, Louzao R, Wilkes S, Datta S, Sarzotti-Kelsoe M, Liao HX, Ferrari G, Alam SM, Montefiori DC, Denny TN, Moody MA, Tomaras GD, Gao F, Haynes BF. Maternal HIV-1 envelope-specific antibody responses and reduced risk of perinatal transmission. J Clin Invest 2015; 125:2702-6. [PMID: 26053661 DOI: 10.1172/jci81593] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 04/30/2015] [Indexed: 12/16/2022] Open
Abstract
Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1-transmitting mothers and 165 propensity score-matched nontransmitting mothers were selected from the Women and Infants Transmission Study (WITS) of US nonbreastfeeding, HIV-1-infected mothers. In a multivariable logistic regression model, the magnitude of the maternal IgG responses specific for the third variable loop (V3) of the HIV-1 envelope was predictive of a reduced risk of MTCT. Neutralizing Ab responses against easy-to-neutralize (tier 1) HIV-1 strains also predicted a reduced risk of peripartum transmission in secondary analyses. Moreover, recombinant maternal V3-specific IgG mAbs mediated neutralization of autologous HIV-1 isolates. Thus, common V3-specific Ab responses in maternal plasma predicted a reduced risk of MTCT and mediated autologous virus neutralization, suggesting that boosting these maternal Ab responses may further reduce HIV-1 MTCT.
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Harms RL, Martinez DR, Griego VM. Isolation and Characterization of Coproporphyrin Produced by Four Subspecies of Bacillus thuringiensis. Appl Environ Microbiol 2010; 51:481-6. [PMID: 16347008 PMCID: PMC238905 DOI: 10.1128/aem.51.3.481-486.1986] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It was found by using spectrophotometric, spectrofluorometric, and high-pressure liquid chromatography that four subspecies of Bacillus thuringiensis produce coproporphyrin. The porphyrin isomer was identified as coproporphyrin I for B. thuringiensis subsp. kurstaki (HD1). The porphyrin was isolated both from spores and from a variety of spent growth media. The quantity of porphyrin released by each Bacillus subspecies differed. The rank order of porphyrin production follows: B. thuringiensis subsp. kurstaki HD1 > B. thuringiensis subsp. thuringiensis HD27 > B. thuringiensis subsp. thuringiensis HD41 > B. thuringiensis subsp. darmstadiensis HD199.
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Martinez DR, Klinghammer E. The Behavior of the Whale Orcinus orca: a Review of the Literature1. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1439-0310.1970.tb01903.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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