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Bhattacharya P, Gannavaram S, Ismail N, Saxena A, Dagur PK, Akue A, KuKuruga M, Nakhasi HL. Toll-like Receptor-9 (TLR-9) Signaling Is Crucial for Inducing Protective Immunity following Immunization with Genetically Modified Live Attenuated Leishmania Parasites. Pathogens 2023; 12:pathogens12040534. [PMID: 37111420 PMCID: PMC10143410 DOI: 10.3390/pathogens12040534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 03/31/2023] Open
Abstract
No human vaccine is available for visceral leishmaniasis (VL). Live attenuated centrin gene-deleted L. donovani (LdCen−/−) parasite vaccine has been shown to induce robust innate immunity and provide protection in animal models. Toll-like receptors (TLRs) are expressed in innate immune cells and are essential for the early stages of Leishmania infection. Among TLRs, TLR-9 signaling has been reported to induce host protection during Leishmania infection. Importantly, TLR-9 ligands have been used as immune enhancers for non-live vaccination strategies against leishmaniasis. However, the function of TLR-9 in the generation of a protective immune response in live attenuated Leishmania vaccines remains unknown. In this study, we investigated the function of TLR-9 during LdCen−/− infection and found that it increased the expression of TLR-9 on DCs and macrophages from ear-draining lymph nodes and spleen. The increase in TLR-9 expression resulted in changes in downstream signaling in DCs mediated through signaling protein myeloid differentiation primary response 88 (MyD88), resulting in activation and nuclear translocation of nuclear factor-κB (NF-κB). This process resulted in an increase in the DC’s proinflammatory response, activation, and DC-mediated CD4+T cell proliferation. Further, LdCen−/− immunization in TLR-9−/− mice resulted in a significant loss of protective immunity. Thus, LdCen−/− vaccine naturally activates the TLR-9 signaling pathway to elicit protective immunity against virulent L. donovani challenge.
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Affiliation(s)
- Parna Bhattacharya
- Division of Emerging and Transfusion Transmitted Disease, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
- Correspondence: (P.B.); (H.L.N.); Tel.: +1-240-402-8209 (H.L.N.)
| | - Sreenivas Gannavaram
- Division of Emerging and Transfusion Transmitted Disease, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Nevien Ismail
- Division of Emerging and Transfusion Transmitted Disease, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Ankit Saxena
- Immune Monitoring Shared Resource, Rutgers, Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA
| | - Pradeep K. Dagur
- Flow Cytometry Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Adovi Akue
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Mark KuKuruga
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Hira L. Nakhasi
- Division of Emerging and Transfusion Transmitted Disease, Center for Biologics Evaluation and Research Food and Drug Administration, Silver Spring, MD 20993, USA
- Correspondence: (P.B.); (H.L.N.); Tel.: +1-240-402-8209 (H.L.N.)
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Tiwari RK, Singh S, Gupta CL, Bajpai P. Microglial TLR9: Plausible Novel Target for Therapeutic Regime Against Glioblastoma Multiforme. Cell Mol Neurobiol 2021; 41:1391-1393. [PMID: 32691190 PMCID: PMC11448552 DOI: 10.1007/s10571-020-00925-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022]
Abstract
An understanding of pattern recognition receptors (PRRs) and immunomodulatory approach based on activation of these receptors has provided insights critical for the management of neurological health disorders. Toll-like receptors (TLRs) are one of the most widely explored PRRs and have been exploited in the recent past for development of novel immunomodulatory therapeutic agents. Glioblastoma multiforme is characterized by significant infiltration of resident microglia and expresses all the members of the TLR family. The present report is focused on exciting findings pertaining to probable implications of TLR9 activation by unmethylated CG sequences for novel therapeutic intervention against glioblastoma multiforme, which could be a discrete step toward the effective management of neurological health issues.
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Affiliation(s)
- Rohit Kumar Tiwari
- Department of Biosciences, Integral University, Kursi Road, Lucknow, Uttar Pradesh, 226026, India
| | - Sarika Singh
- Division of Toxicology, CSIR-Central Drug Research Institute, B.S. 10/1, Sector-10, Jankipuram Extension, Lucknow, Uttar Pradesh, 226031, India
| | - Chhedi Lal Gupta
- Institute of Soil, Water and Environmental Sciences, Volcani Research Center, ARO, 68 HaMacabim Rd, P.O Box 15159, 7528809, Rishon Lezion, Israel
| | - Preeti Bajpai
- Department of Biosciences, Integral University, Kursi Road, Lucknow, Uttar Pradesh, 226026, India.
- Department of Zoology, Mahatma Gandhi Central University, Motihari, East Champaran, Bihar, 845401, India.
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