Toll- like receptor-2 mediates local innate immune response against Trypanosoma cruzi in ex vivo infected human placental chorionic villi explants

ABSTRACT The innate immune response to Pneumocystis infection is not well understood. In this study, normal C57BL/6 mouse alveolar macrophages were found to respond to Pneumocystis murina organisms through Toll-like receptor 2 (TLR2), leading to the nuclear translocation of NF-κB and the production of proinflammatory cytokine tumor necrosis factor alpha (TNF-α) and chemokine macrophage inflammatory protein 2 (MIP-2). P. murina stimulation of normal alveolar macrophages from C57BL/6 mice resulted in increased TLR2 transcription but not increased TLR4 transcription. In gain-of-function studies with HEK293 cells expressing TLR2 or TLR4, only TLR2 was found to stimulate an NF-κB response to P. murina. TNF-α and MIP-2 production in response to P. murina by mouse alveolar macrophages was inhibited by a monoclonal antibody that specifically blocked the ligand-binding ability of TLR2. Alveolar macrophages from TLR2 knockout (TLR2−/−) mice showed little increase in TNF-α and MIP-2 mRNA levels upon P. murina stimulation. An in vivo study showed that TLR2−/− mice challenged with P. murina had reduced cytokine responses. These results indicate that TLR2 plays a major role in the innate immune response to P. murina.

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Arg753Gln Polymorphisms in the Toll-Like Receptor 2 Gene are Associated with Cytomegalovirus Infection in Egyptian Bone Marrow Recipients

Endocrine Metabolic & Immune Disorders - Drug Targets ◽

10.2174/1871530319666191018124710 ◽

2020 ◽

Vol 20 (4) ◽

pp. 619-624

Author(s):

Sobhy Hassab El-Nabi ◽

Samia Sayed ◽

Mohamed A. Abd-Elhafez ◽

Mohamed Elfiky ◽

Ahmed E. Abdel Moneim ◽

...

Keyword(s):

Bone Marrow ◽

Immune Response ◽

Bone Marrow Transplantation ◽

Innate Immune Response ◽

Marrow Transplantation ◽

Innate Immune ◽

Toll Like Receptor ◽

Cmv Infection ◽

Tlr2 Gene ◽

Toll Like Receptor 2

Background: Previous studies have shown that cytomegalovirus (CMV) induced innate immune response via activation of Toll-like receptor 2 (TLR2). The association between CMV among specific single-nucleotide polymorphisms (SNPs) in the TLR2 gene was also investigated. Objective: This study investigated the relationship between specific SNPs in the TLR2 gene (G>A), TLR2-Arg753Gln (rs5743708), and CMV replication after bone marrow transplantation. Methods: The TLR2-Arg753Gln SNP was genotyped in 181 patients after bone marrow transplantation: 83 and 98 patients with and without CMV infection, respectively. CMV load was determined in serially collected blood samples using real-time PCR. Genotyping was performed using specific sequence primer PCR (SSP-PCR), and the results were confirmed by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified fragments for GG (wild type), GA and AA identification. Results: Roughly, 85% of the patients screened for the presence of the TLR2-Arg753Gln were GG homozygous, and 15% were GA heterozygous; no patients were homozygous for the mutant allele (A). The GA heterozygous allele was more frequent in the CMV-infected group after bone marrow transplantation. Conclusion: To our knowledge, this is a novel observation that supports the notion that the functional missense mutation (TLR2-Arg753Gln polymorphism) is possibly associated with CMV replication after bone marrow transplantation. This suggests a role for TLR2 in the innate immune response of human CMV infection in Egyptian bone marrow recipients..

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