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Malladi SK, Singh R, Pandey S, Gayathri S, Kanjo K, Ahmed S, Khan MS, Kalita P, Girish N, Upadhyaya A, Reddy P, Pramanick I, Bhasin M, Mani S, Bhattacharyya S, Joseph J, Thankamani K, Raj VS, Dutta S, Singh R, Nadig G, Varadarajan R. Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment. J Biol Chem 2021; 296:100025. [PMID: 33154165 PMCID: PMC7832000 DOI: 10.1074/jbc.ra120.016284] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 12/19/2022] Open
Abstract
Virtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Furthermore, several of them use viral vectors or mRNA. In contrast to protein subunit vaccines, there is limited manufacturing expertise for these nucleic-acid-based modalities, especially in the developing world. Neutralizing antibodies, the clearest known correlate of protection against SARS-CoV-2, are primarily directed against the receptor-binding domain (RBD) of the viral spike protein, suggesting that a suitable RBD construct might serve as a more accessible vaccine ingredient. We describe a monomeric, glycan-engineered RBD protein fragment that is expressed at a purified yield of 214 mg/l in unoptimized, mammalian cell culture and, in contrast to a stabilized spike ectodomain, is tolerant of exposure to temperatures as high as 100 °C when lyophilized, up to 70 °C in solution and stable for over 4 weeks at 37 °C. In prime:boost guinea pig immunizations, when formulated with the MF59-like adjuvant AddaVax, the RBD derivative elicited neutralizing antibodies with an endpoint geometric mean titer of ∼415 against replicative virus, comparing favorably with several vaccine formulations currently in the clinic. These features of high yield, extreme thermotolerance, and satisfactory immunogenicity suggest that such RBD subunit vaccine formulations hold great promise to combat COVID-19.
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MESH Headings
- Angiotensin-Converting Enzyme 2/chemistry
- Angiotensin-Converting Enzyme 2/genetics
- Angiotensin-Converting Enzyme 2/immunology
- Animals
- Antibodies, Neutralizing/biosynthesis
- Antibodies, Viral/biosynthesis
- Binding Sites
- COVID-19/immunology
- COVID-19/prevention & control
- COVID-19/virology
- COVID-19 Vaccines/administration & dosage
- COVID-19 Vaccines/biosynthesis
- COVID-19 Vaccines/genetics
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Female
- Guinea Pigs
- HEK293 Cells
- Hot Temperature
- Humans
- Immunogenicity, Vaccine
- Models, Molecular
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Domains
- Protein Interaction Domains and Motifs
- Protein Stability
- Receptors, Virus/chemistry
- Receptors, Virus/genetics
- Receptors, Virus/immunology
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- SARS-CoV-2/chemistry
- SARS-CoV-2/immunology
- Spike Glycoprotein, Coronavirus/chemistry
- Spike Glycoprotein, Coronavirus/genetics
- Spike Glycoprotein, Coronavirus/immunology
- Vaccination
- Vaccine Potency
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Affiliation(s)
| | - Randhir Singh
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Suman Pandey
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Savitha Gayathri
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Kawkab Kanjo
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Shahbaz Ahmed
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | | | - Parismita Kalita
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Nidhi Girish
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Aditya Upadhyaya
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Poorvi Reddy
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Ishika Pramanick
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Munmun Bhasin
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Shailendra Mani
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, India
| | - Sankar Bhattacharyya
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, India
| | - Jeswin Joseph
- Virology Scientific Research (VSR) Laboratory, School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Kerala, India
| | - Karthika Thankamani
- Virology Scientific Research (VSR) Laboratory, School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Kerala, India
| | - V Stalin Raj
- Virology Scientific Research (VSR) Laboratory, School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Kerala, India
| | - Somnath Dutta
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India
| | - Ramandeep Singh
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, India
| | - Gautham Nadig
- Mynvax Private Limited, ES12, Entrepreneurship Centre, SID, Indian Institute of Science, Bengaluru, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit (MBU), Indian Institute of Science, Bengaluru, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India.
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Padilla-Carlin DJ, McMurray DN, Hickey AJ. The guinea pig as a model of infectious diseases. Comp Med 2008; 58:324-340. [PMID: 18724774 PMCID: PMC2706043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 12/05/2007] [Accepted: 12/27/2007] [Indexed: 05/26/2023]
Abstract
The words 'guinea pig' are synonymous with scientific experimentation, but much less is known about this species than many other laboratory animals. This animal model has been used for approximately 200 y and was the first to be used in the study of infectious diseases such as tuberculosis and diphtheria. Today the guinea pig is used as a model for a number of infectious bacterial diseases, including pulmonary, sexually transmitted, ocular and aural, gastrointestinal, and other infections that threaten the lives of humans. Most studies on the immune response to these diseases, with potential therapies and vaccines, have been conducted in animal models (for example, mouse) that may have less similarity to humans because of the large number of immunologic reagents available for these other species. This review presents some of the diseases for which the guinea pig is regarded as the premier model to study infections because of its similarity to humans with regard to symptoms and immune response. Furthermore, for diseases in which guinea pigs share parallel pathogenesis of disease with humans, they are potentially the best animal model for designing treatments and vaccines. Future studies of immune regulation of these diseases, novel therapies, and preventative measures require the development of new immunologic reagents designed specifically for the guinea pig.
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Affiliation(s)
- Danielle J Padilla-Carlin
- School of Pharmacy, Division of Molecular Pharmaceutics, University of North Carolina, Chapel Hill, NC
| | - David N McMurray
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, College Station, TX
| | - Anthony J Hickey
- School of Pharmacy, Division of Molecular Pharmaceutics, University of North Carolina, Chapel Hill, NC
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Weeratna R, Stamler DA, Edelstein PH, Ripley M, Marrie T, Hoskin D, Hoffman PS. Human and guinea pig immune responses to Legionella pneumophila protein antigens OmpS and Hsp60. Infect Immun 1994; 62:3454-62. [PMID: 7913699 PMCID: PMC302978 DOI: 10.1128/iai.62.8.3454-3462.1994] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We studied the immune responses of guinea pigs and humans to two Legionella pneumophila antigens. Guinea pigs surviving a lethal intraperitoneal challenge dose of virulent L. pneumophila exhibited strong cutaneous delayed-type hypersensitivity (DTH) reactions to purified OmpS (28-kDa major outer membrane protein) and Hsp60 (heat shock protein or common antigen), while weak DTH reactions were noted for extracellular protease (major secretory protein [MSP] [ProA]) and no reaction was observed with an ovalbumin (OA) control. Lymphocyte proliferation responses (LPRs) were measured for peripheral blood and spleen lymphocytes from guinea pigs surviving sublethal and lethal challenge doses of L. pneumophila. Lymphocytes from uninfected animals showed no proliferation to Hsp60 or OmpS, while lymphocytes from sublethally and lethally challenged animals exhibited strong proliferative responses to Hsp60 and OmpS. Guinea pigs vaccinated with purified OmpS exhibited low antibody titers and strong DTH and LPRs to OmpS, whereas lymphocytes from animals vaccinated with Hsp60 exhibited weak DTH responses and high antibody titers to Hsp60. All guinea pigs immunized with OmpS survived experimental challenge with L. pneumophila (two of two in a pilot study and seven of seven in trial 2) versus zero of seven OA-immunized controls (P = 0.006 by Fisher's exact test). In three vaccine trials in which animals were vaccinated with Hsp60, only 1 guinea pig of 15 survived lethal challenge. Peripheral blood lymphocytes (PBLs) from humans with legionellosis showed stronger LPRs to OmpS than PBLs from humans with no history of legionellosis (P = 0.0002 by Mann-Whitney test). PBLs of humans surviving legionellosis exhibited a lower but highly significant proliferative response to Hsp60 (P < 0.0001 compared with controls by Mann-Whitney test). These studies indicate that OmpS and Hsp60 are important antigens associated with the development of protective cellular immunity. However, as determined in vaccine trial studies in the guinea pig model for legionellosis, the species-specific antigen OmpS proved much more effective than the genus-common Hsp60 antigen.
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Affiliation(s)
- R Weeratna
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
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Klein TW, Yamamoto Y, Wilson S, Newton C, Friedman H. Legionella pneumophila infection and cytokine production. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1992; 319:97-104. [PMID: 1414610 DOI: 10.1007/978-1-4615-3434-1_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- T W Klein
- Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa 33612
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6
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Hoffman PS, Houston L, Butler CA. Legionella pneumophila htpAB heat shock operon: nucleotide sequence and expression of the 60-kilodalton antigen in L. pneumophila-infected HeLa cells. Infect Immun 1990; 58:3380-7. [PMID: 2205580 PMCID: PMC313664 DOI: 10.1128/iai.58.10.3380-3387.1990] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A 60-kilodalton (kDa) immunodominant antigen of Legionella pneumophila is a heat shock protein (HSP) of the GroEL class of HSPs. The gene (htpB) coding the 60-kDa protein was localized to a 3.2-kilobase DNA fragment of L. pneumophila cloned into pUC19 (pSH16) (P. S. Hoffman, C. A. Butler, and F. D. Quinn, Infect. Immun. 57:1731-1739, 1989). The nucleotide sequence of the DNA fragment cloned into M13 confirmed two open reading frames, htpA and htpB, that code for proteins of 96 and 548 amino acids, respectively. A consensus heat shock promoter sequence upstream of the start of htpA was identified, and no obvious promoter sequences were detected upstream of htpB. Amino acid sequence comparison studies revealed that the L. pneumophila HtpB protein exhibited 76% homology with the 65-kDa protein of Mycobacterium tuberculosis and 85% homology with both GroEL of Escherichia coli and HtpB of Coxiella burnetii. A comparison of the amino acid sequences among these proteins revealed several regions of nearly absolute sequence conservation, with the variable regions occurring in common areas. The purified L. pneumophila 60-kDa protein was antigenic for human T lymphocytes. Indirect fluorescent antibody studies indicated that the 60-kDa protein may be located in the periplasm or expressed on the surface by intracellular bacteria, suggesting that a stress-related mechanism may be involved in the expression of this immunodominant antigen.
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Affiliation(s)
- P S Hoffman
- Department of Microbiology and Immunology, University of Tennessee, Memphis 38163
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7
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Nikaido Y, Yoshida S, Goto Y, Mizuguchi Y, Kuroiwa A. Macrophage-activating T-cell factor(s) produced in an early phase of Legionella pneumophila infection in guinea pigs. Infect Immun 1989; 57:3458-65. [PMID: 2807531 PMCID: PMC259853 DOI: 10.1128/iai.57.11.3458-3465.1989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Protective immunity of guinea pigs against Legionella pneumophila was studied by infecting the animals with a sublethal dose (about 2 x 10(4) CFU) of the organism. The bacteria multiplied in the liver, spleen, and lungs up to day 4 after the intraperitoneal infection. The live bacteria in these organs decreased quickly thereafter and were eliminated by day 7. A delayed-type skin reaction and lymphoproliferation of spleen cells to Formalin-killed L. pneumophila were detected from days 5 and 6, respectively, after infection. Peritoneal macrophages obtained from guinea pigs infected 6 days previously inhibited the intracellular growth of L. pneumophila. Antigen-stimulated spleen cell factor prepared from infected guinea pigs inhibited the intracellular growth of the organism in macrophages obtained from uninfected animals. Antigen-stimulated spleen cell factor prepared from spleen cells treated with anti-guinea pig T-cell monoclonal antibody did not inhibit growth. The activity of antigen-stimulated spleen cell factor was labile to pH 2 treatment, and the factor could not be absorbed by L. pneumophila antigen, suggesting that it contains gamma interferon. Our data show that T-cell-mediated immunity begins to work from an early period of infection with L. pneumophila in guinea pigs.
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Affiliation(s)
- Y Nikaido
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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Dournon E. Modeles animaux d'infection a Legionella. Med Mal Infect 1989. [DOI: 10.1016/s0399-077x(89)80103-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Friedman H, Klein TW, Widen R, Newton C, Blanchard DK, Yamamoto Y. Legionella pneumophila immunity and immunomodulation: nature and mechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 239:327-41. [PMID: 3059772 DOI: 10.1007/978-1-4757-5421-6_32] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
L. pneumophila is a facultative intracellular opportunistic pathogen ubiquitously present in the environment. Much is now known concerning the ecological niche of this organism as well as many other characteristics of these bacteria, including physiology and biochemistry. However, much less is known about immune mechanisms responsible for host resistance vs susceptibility. Not only outer membrane protein rich fractions but also LPS-rich components are potent immunogens, both in experimental animals such as susceptible guinea pigs and more resistant rodent species like rats and mice. Immunity to these organisms can be readily observed by a variety of serologic techniques. Antibody titers increase rapidly after exposure of individuals to these bacteria either by infection or immunization. However, such antibody does not appear to play an important role in host resistance. Serum antibody plus complement is not lytic for the bacteria in vitro. Furthermore, antibody appears to promote the phagocytosis of the bacteria by monocytes and/or macrophages in culture but such phagocytosis does not result in killing of the bacteria, merely an enhanced uptake and subsequent replication of the organisms. Studies on cellular immunity have focused attention on the role of T lymphocytes, monocytes and macrophages. In addition, cutaneous hypersensitivity is readily induced by infection or immunization of experimental animals with Legionella or antigenic components. In vitro correlates of hypersensitivity is also readily evident after infection or immunization. Although lymphoid cells from guinea pigs only show evidence of responsiveness to Legionella antigens by the lymphocyte blastogenic reaction after animals have been sensitized, peripheral blood monocytes from man as well as splenocytes from mice show evidence of responsiveness to Legionella even before known infection or sensitization. However, higher blastogenic responses become evident after sensitization or infection. In addition, interleukins, such as interleukin 1 and 2, as well as interferon and tumor necrotizing factor, appear in response to Legionella antigens and seem to play a role in resistance mechanisms. Cellular replication of Legionella in monocytes from man as well as macrophages from susceptible animals seems related to susceptibility or resistance to these organisms. Further analyses of the nature and mechanism of humoral vs cellular immune responses to Legionella antigens will provide valuable information about immunity and resistance to these intracellular pathogens in susceptible individuals.
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Affiliation(s)
- H Friedman
- Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa 33612
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Klein TW, Newton CA, Blanchard DK, Widen R, Friedman H. Induction of interleukin 1 by Legionella pneumophila antigens in mouse macrophage and human mononuclear leukocyte cultures. ZENTRALBLATT FUR BAKTERIOLOGIE, MIKROBIOLOGIE, UND HYGIENE. SERIES A, MEDICAL MICROBIOLOGY, INFECTIOUS DISEASES, VIROLOGY, PARASITOLOGY 1987; 265:462-71. [PMID: 3499724 DOI: 10.1016/s0176-6724(87)80265-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Exposure to Legionella pneumophila antigens has been reported to result in both an adjuvant effect and pathophysiological changes such as fever, headache, myalgia and arthralgias. Immunoenhancement and inflammatory changes have been associated with the production of interleukin 1, and we, therefore, sought an involvement of interleukin production in the alteration of biological responsiveness following exposure to Legionella pneumophila antigens. Killed Legionella pneumophila cells, incubated with mouse splenocytes, induced the formation of a soluble substance which enhanced splenocyte antibody production to heterologous antigen. The immunoenhancing substance was also produced by mouse peritoneal macrophages and supernatants from these cultures were demonstrated to also contain thymocyte co-mitogenic activity. Following gel filtration, this co-mitogenic activity eluted in the 15,000 molecular weight range suggesting an involvement of interleukin 1. Experiments with Legionella pneumophila cells, and cell extracts containing endotoxin, and purified endotoxin suggested that the interleukin 1 activity was induced by both endotoxin and non-endotoxin antigens. The Legionella pneumophila antigens were also found to be potent inducers of interleukin 1 activity in human peripheral blood mononuclear cell cultures. These results suggest that Legionella pneumophila antigens are potent inducers of interleukin 1 in both mouse and human cells. The induction of this monokine may partially account for both the immunoenhancing property of this bacterial species and the associated pathophysiological changes following infection with this microorganism.
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Affiliation(s)
- T W Klein
- Department Medical Microbiology and Immunology, University of South Florida, College of Medicine, Tampa 33612
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