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Baz AA, Hao H, Lan S, Li Z, Liu S, Chen S, Chu Y. Neutrophil extracellular traps in bacterial infections and evasion strategies. Front Immunol 2024; 15:1357967. [PMID: 38433838 PMCID: PMC10906519 DOI: 10.3389/fimmu.2024.1357967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/26/2024] [Indexed: 03/05/2024] Open
Abstract
Neutrophils are innate immune cells that have a vital role in host defense systems. Neutrophil extracellular traps (NETs) are one of neutrophils' defense mechanisms against pathogens. NETs comprise an ejected lattice of chromatin associated with histones, granular proteins, and cytosolic proteins. They are thought to be an efficient strategy to capture and/or kill bacteria and received intensive research interest in the recent years. However, soon after NETs were identified, it was observed that certain bacteria were able to evade NET entrapment through many different mechanisms. Here, we outline the recent progress of NETs in bacterial infections and the strategies employed by bacteria to evade or withstand NETs. Identifying the molecules and mechanisms that modulate NET release will improve our understanding of the functions of NETs in infections and provide new avenues for the prevention and treatment of bacterial diseases.
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Affiliation(s)
- Ahmed Adel Baz
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assiut, Egypt
| | - Huafang Hao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
| | - Shimei Lan
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
| | - Zhangcheng Li
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
| | - Shuang Liu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
| | - Shengli Chen
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
| | - Yuefeng Chu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, China
- Key Laboratory of Ruminant Disease Prevention and Control (West), Ministry of Agricultural and Rural Affairs, Lanzhou, China
- Key Laboratory of Veterinary Etiological Biology, Ministry of Agricultural and Rural Affairs, Lanzhou, China
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Bonhomme D, Cavaillon JM, Werts C. The dangerous liaisons in innate immunity involving recombinant proteins and endotoxins: Examples from the literature and the Leptospira field. J Biol Chem 2024; 300:105506. [PMID: 38029965 PMCID: PMC10777017 DOI: 10.1016/j.jbc.2023.105506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/15/2023] [Accepted: 11/20/2023] [Indexed: 12/01/2023] Open
Abstract
Endotoxins, also known as lipopolysaccharides (LPS), are essential components of cell walls of diderm bacteria such as Escherichia coli. LPS are microbe-associated molecular patterns that can activate pattern recognition receptors. While trying to investigate the interactions between proteins and host innate immunity, some studies using recombinant proteins expressed in E. coli reported interaction and activation of immune cells. Here, we set out to provide information on endotoxins that are highly toxic to humans and bind to numerous molecules, including recombinant proteins. We begin by outlining the history of the discovery of endotoxins, their receptors and the associated signaling pathways that confer extreme sensitivity to immune cells, acting alone or in synergy with other microbe-associated molecular patterns. We list the various places where endotoxins have been found. Additionally, we warn against the risk of data misinterpretation due to endotoxin contamination in recombinant proteins, which is difficult to estimate with the Limulus amebocyte lysate assay, and cannot be completely neutralized (e.g., treatment with polymyxin B or heating). We further illustrate our point with examples of recombinant heat-shock proteins and viral proteins from severe acute respiratory syndrome coronavirus 2, dengue and HIV, for which endotoxin contamination has eventually been shown to be responsible for the inflammatory roles previously ascribed. We also critically appraised studies on recombinant Leptospira proteins regarding their putative inflammatory roles. Finally, to avoid these issues, we propose alternatives to express recombinant proteins in nonmicrobial systems. Microbiologists wishing to undertake innate immunity studies with their favorite pathogens should be aware of these difficulties.
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Affiliation(s)
- Delphine Bonhomme
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
| | | | - Catherine Werts
- Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France.
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Varma VP, Kadivella M, Kavela S, Faisal SM. Leptospira Lipid A Is a Potent Adjuvant That Induces Sterilizing Immunity against Leptospirosis. Vaccines (Basel) 2023; 11:1824. [PMID: 38140228 PMCID: PMC10748165 DOI: 10.3390/vaccines11121824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/16/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Leptospirosis is a globally significant zoonotic disease. The current inactivated vaccine offers protection against specific serovars but does not provide complete immunity. Various surface antigens, such as Leptospira immunoglobulin-like proteins (LigA and LigB), have been identified as potential subunit vaccine candidates. However, these antigens require potent adjuvants for effectiveness. Bacterial lipopolysaccharides (LPSs), including lipid A, are a well-known immunostimulant, and clinical adjuvants often contain monophosphoryl lipid A (MPLA). Being less endotoxic, we investigated the adjuvant properties of lipid A isolated from L. interrogans serovar Pomona (PLA) in activating innate immunity and enhancing antigen-specific adaptive immune responses. PLA activated macrophages to a similar degree as MPLA, albeit at a higher dose, suggesting that it is less potent in stimulation than MPLA. Mice immunized with a variable portion of LigA (LAV) combined with alum and PLA (LAV-alum-PLA) exhibited significantly higher levels of LAV-specific humoral and cellular immune responses compared to alum alone but similar to those induced by alum-MPLA. The adjuvant activity of PLA resembles that of MPLA and is primarily achieved through the increased recruitment, activation, and uptake of antigens by innate immune cells. Furthermore, like MPLA, PLA formulation establishes a long-lasting memory response. Notably, PLA demonstrated superior potency than MPLA formulation and provided sterilizing immunity against the leptospirosis in a hamster model. Overall, our study sheds light on the adjuvant properties of Leptospira lipid A and offers promising avenues for developing LPS-based vaccines against this devastating zoonotic disease.
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Affiliation(s)
- Vivek P. Varma
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Mohammad Kadivella
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Regional Centre for Biotechnology, Faridabad 121001, India
| | - Sridhar Kavela
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
| | - Syed M. Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad 500032, India; (V.P.V.); (M.K.); (S.K.)
- Regional Centre for Biotechnology, Faridabad 121001, India
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Li X, Xiao S, Filipczak N, Yalamarty SSK, Shang H, Zhang J, Zheng Q. Role and Therapeutic Targeting Strategies of Neutrophil Extracellular Traps in Inflammation. Int J Nanomedicine 2023; 18:5265-5287. [PMID: 37746050 PMCID: PMC10516212 DOI: 10.2147/ijn.s418259] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
Neutrophil extracellular traps (NETs) are large DNA reticular structures secreted by neutrophils and decorated with histones and antimicrobial proteins. As a key mechanism for neutrophils to resist microbial invasion, NETs play an important role in the killing of microorganisms (bacteria, fungi, and viruses). Although NETs are mostly known for mediating microbial killing, increasing evidence suggests that excessive NETs induced by stimulation of physical and chemical components, microorganisms, and pathological factors can exacerbate inflammation and organ damage. This review summarizes the induction and role of NETs in inflammation and focuses on the strategies of inhibiting NETosis and the mechanisms involved in pathogen evasion of NETs. Furthermore, herbal medicine inhibitors and nanodelivery strategies improve the efficiency of inhibition of excessive levels of NETs.
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Affiliation(s)
- Xiang Li
- National Pharmaceutical Engineering Center for Solid Preparation in Chinese Herbal Medicine, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, People’s Republic of China
| | - Shanghua Xiao
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, People’s Republic of China
| | - Nina Filipczak
- Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA, USA
| | | | - Hongming Shang
- Department of Biochemistry & Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - Jing Zhang
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, People’s Republic of China
| | - Qin Zheng
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, People’s Republic of China
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de Jesus Gonzalez-Contreras F, Zarate X. Neutrophil extracellular traps: Modulation mechanisms by pathogens. Cell Immunol 2022; 382:104640. [PMID: 36413806 DOI: 10.1016/j.cellimm.2022.104640] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/03/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022]
Abstract
Neutrophils, as innate effector cells, play an essential role in the containment and elimination of pathogens. Among the main neutrophil mechanisms use for these processes is the release of neutrophil extracellular traps (NETs), which consist of decondensed DNA decorated with various cytoplasmic proteins. NETs' principal role is the trapping and elimination of infectious agents; therefore, the formation of NETs is regulated by bacteria, fungi, parasites, and viruses through different mechanisms: the presence of virulence factors (adhered or secreted), microbial load, size of the microorganism, and even due to other immune cells activation (mainly platelets). This review summarizes the significant aspects that contribute to NETs modulation by pathogens and their components, and the effect NETs have on these pathogens as a cellular defense mechanism.
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Affiliation(s)
| | - Xristo Zarate
- Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, San Nicolas de los Garza 66455, NL, Mexico
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Varma VP, Kadivella M, Kumar A, Kavela S, Faisal SM. LigA formulated in AS04 or Montanide ISA720VG induced superior immune response compared to alum, which correlated to protective efficacy in a hamster model of leptospirosis. Front Immunol 2022; 13:985802. [PMID: 36300125 PMCID: PMC9590693 DOI: 10.3389/fimmu.2022.985802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospirosis is a zoonotic disease of global importance. The current vaccine provides serovar-specific and short-term immunity and does not prevent bacterial shedding in infected animals. Subunit vaccines based on surface proteins have shown to induce protection in an animal model. However, these proteins were tested with non-clinical adjuvants and induced low to moderate protective efficacy. We formulated a variable region of Leptospira immunoglobulin-like protein A (LAV) in clinical adjuvants, AS04 and Montanide ISA720VG, and then evaluated the immune response in mice and protective efficacy in a hamster model. Our results show that animals immunized with LAV-AS04 and LAV-Montanide ISA720VG (LAV-M) induced significantly higher levels of LAV-specific antibodies than LAV-Alum. While LAV-Alum induced Th2 response with the induction of IgG1 and IL-4, AS04 and LAV-M induced a mixed Th1/Th2 response with significant levels of both IgG1/IL-4 and IgG2c/IFN-γ. Both LAV-AS04 and LAV-M induced the generation of a significantly higher number of cytotoxic T cells (CTLs). The immune response in LAV-AS04- and LAV-M-immunized animals was maintained for a long period (>180 days) with the generation of a significant level of B- and T-cell memory. The strong immune response by both vaccines correlated to enhanced recruitment and activation of innate immune cells particularly DCs at draining lymph nodes and the formation of germinal centers (GCs). Furthermore, the immune response generated in mice correlated to protective efficacy in the hamster model of leptospirosis. These results indicate that LAV-AS04 and LAV-M are promising vaccines and can be further evaluated in clinical trials.
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Affiliation(s)
- Vivek P. Varma
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Mohammad Kadivella
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India
- Regional Centre for Biotechnology, Faridabad, India
| | - Ajay Kumar
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India
- Regional Centre for Biotechnology, Faridabad, India
| | - Sridhar Kavela
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India
| | - Syed M. Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India
- Regional Centre for Biotechnology, Faridabad, India
- *Correspondence: Syed M. Faisal,
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Liao C, Mao F, Qian M, Wang X. Pathogen-Derived Nucleases: An Effective Weapon for Escaping Extracellular Traps. Front Immunol 2022; 13:899890. [PMID: 35865526 PMCID: PMC9294136 DOI: 10.3389/fimmu.2022.899890] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Since the 2004 publication of the first study describing extracellular traps (ETs) from human neutrophils, several reports have shown the presence of ETs in a variety of different animals and plants. ETs perform two important functions of immobilizing and killing invading microbes and are considered a novel part of the phagocytosis-independent, innate immune extracellular defense system. However, several pathogens can release nucleases that degrade the DNA backbone of ETs, reducing their effectiveness and resulting in increased pathogenicity. In this review, we examined the relevant literature and summarized the results on bacterial and fungal pathogens and parasites that produce nucleases to evade the ET-mediated host antimicrobial mechanism.
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Affiliation(s)
- Chengshui Liao
- College of Animal Science and Technology/Luoyang Key Laboratory of Live Carrier Biomaterial and Animal Disease Prevention and Control, Henan University of Science and Technology, Luoyang, China
- *Correspondence: Chengshui Liao, ; Xiaoli Wang,
| | - Fuchao Mao
- College of Animal Science and Technology/Luoyang Key Laboratory of Live Carrier Biomaterial and Animal Disease Prevention and Control, Henan University of Science and Technology, Luoyang, China
- Animal Diseases and Public Health Engineering Research Center of Henan Province, Luoyang Vocational and Technical College, Luoyang, China
| | - Man Qian
- College of Animal Science and Technology/Luoyang Key Laboratory of Live Carrier Biomaterial and Animal Disease Prevention and Control, Henan University of Science and Technology, Luoyang, China
| | - Xiaoli Wang
- School of Basic Medical Sciences, Henan University of Science and Technology, Luoyang, China
- *Correspondence: Chengshui Liao, ; Xiaoli Wang,
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Kumar A, Varma VP, Faisal SM. Screening of Surface-Exposed Lipoproteins of Leptospira Involved in Modulation of Host Innate Immune Response. Front Microbiol 2022; 13:761670. [PMID: 35401498 PMCID: PMC8988195 DOI: 10.3389/fmicb.2022.761670] [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] [Received: 08/20/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Leptospira, a zoonotic pathogen, is capable of causing both chronic and acute infection in a susceptible host. Surface-exposed lipoproteins play a major role in modulating the host immune response by activating the innate cells like macrophages and dendritic cells or evading complement attack and killing by phagocytes like neutrophils to favor pathogenesis and establish infection. In this study, we screened some surface-exposed lipoproteins known to be involved in pathogenesis to assess their possible role in immune modulation (innate immune activation or evasion). Surface proteins of the Len family (LenB, LenD, and LenE), Lsa30, Loa22, and Lipl21 were purified in recombinant form and then tested for their ability to activate macrophages of the different host (mouse, human, and bovine). These proteins were tested for binding with complement regulators like Factor H (FH), C4 Binding Protein (C4BP), and host protease Plasminogen (PLG) and also as nucleases to access their possible role in innate immune evasion. Our results show that, of various proteins tested, Loa22 induced strong innate activation and Lsa30 was least stimulatory, as evident from the production of pro-inflammatory cytokines (interleukin-6 and tumor necrosis factor–α) and expression of surface markers [CD80, CD86, and major histocompatibility complex class II (MHCII)]. All the tested proteins were able to bind to FH, C4BP, and PLG; however, Loa22 showed strong binding to PLG correlating to plasmin activity. All the proteins except Loa22 showed nuclease activity, albeit with a requirement of different metal ions. The nuclease activity of these proteins correlated to in vitro degradation of neutrophil extracellular trap (NET). In conclusion, our results indicate that these surface proteins are involved in innate immune modulation and may play a critical role in assisting the bacteria in invading and colonizing the host tissue for persistent infection.
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Affiliation(s)
- Ajay Kumar
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Regional Center for Biotechnology, Faridabad, India
| | - Vivek P Varma
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Syed M Faisal
- Laboratory of Vaccine Immunology, National Institute of Animal Biotechnology, Hyderabad, India.,Regional Center for Biotechnology, Faridabad, India
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