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Nucleotide oligomerization and binding domain (NOD)-like receptors (NLRs) are important in the innate immune response to viral infection. Recent findings have implicated NLRP3, NOD2, and NLRX1 as important players in the innate antiviral response, but their roles in the generation of adaptive immunity to viruses are less clear. We demonstrate here that NOD2 is critical for both innate and adaptive immune responses necessary for controlling viral replication and survival during influenza A virus (IAV) infection. Nod2-/- mice have reduced beta interferon (IFN-β) levels and fewer activated dendritic cells (DCs), and the DCs are more prone to cell death in the lungs of Nod2-/- mice during IAV infection. In agreement with the role for DCs in priming adaptive immunity, the generation of virus-specific CD8+ T cells and their activation and production of IFN-γ were lower in Nod2-/- mice. Furthermore, Nod2-/- DCs, when cocultured with T cells in vitro, have a lower costimulatory capacity. Thus, Nod2-/- DCs are unable to efficiently prime CD8+ T cells. These findings demonstrate that Nod2 is critical for the generation of both innate and adaptive immune responses necessary for controlling IAV infection. [ABSTRACT FROM AUTHOR]

Abstract: Human Respiratory Syncytial Virus (HRSV) is an important pathogen and is associated with mortality in the young, old, and immuno-compromised. Due to the lack of effective therapeutic antivirals or a vaccine, there is a critical need for continued research in this field. Here we tested the ability of the FDA approved proteasome inhibitor bortezomib to inhibit HRSV in vitro and in vivo. We observed significant inhibition of HRSV replication in Vero cells at bortezomib concentrations from 20 to 40ng/ml. Bortezomib was well tolerated in mice when administered intranasally at concentrations of ≤0.3mg/kg or intraperitoneally at 1.0mg/kg. However, treatment of HRSV-infected mice with doses as low as 0.01mg/kg resulted in increased pulmonary inflammation and mortality compared to mock treated-infected control animals. Examination of cytokine expression levels from lungs of bortezomib treated HRSV-infected mice revealed an increase in G-CSF, IL-6, MCP-1, and RANTES levels and a decrease in total IL-12 compared to mock treated-infected control animals. These data indicate that treatment with bortezomib during HRSV infection may alter the immune response and could potentially create a risk for patients treated with bortezomib in the event of a respiratory tract infection. [Copyright &y& Elsevier]

The innate immune system detects the presence of pathogens based on detection of non-self. In other words, most pathogens possess intrinsic differences that can distinguish them from host cells. For example, bacteria and fungi have cell walls comprised of peptidoglycan and carbohydrates (like mannans), respectively. Germline encoded pattern recognition receptors (PRRs) of the Toll-like receptor (TLR) and C-type lectin receptor (CLR) family have the ability to detect such unique pathogen associated features. However, some TLRs and members of the RIG-I-like receptor (RLR), NOD-like receptor (NLR), or AIM2-like receptor (ALR) family can sense pathogen invasion based on pathogen nucleic acids. Nucleic acids are not unique to pathogens, thus raising the question of how such PRRs evolved to detect pathogens but not self. In this chapter, we will examine the PRRs that sense pathogen nucleic acids and subsequently activate the inflammasome signaling pathway. We will examine the selective mechanisms by which these receptors distinguish pathogens from "self" and discuss the importance of such pathways in disease development in animal models and human patients., (© 2019 Elsevier Inc. All rights reserved.)

Unlabelled: Nucleotide oligomerization and binding domain (NOD)-like receptors (NLRs) are important in the innate immune response to viral infection. Recent findings have implicated NLRP3, NOD2, and NLRX1 as important players in the innate antiviral response, but their roles in the generation of adaptive immunity to viruses are less clear. We demonstrate here that NOD2 is critical for both innate and adaptive immune responses necessary for controlling viral replication and survival during influenza A virus (IAV) infection. Nod2(-/-) mice have reduced beta interferon (IFN-β) levels and fewer activated dendritic cells (DCs), and the DCs are more prone to cell death in the lungs of Nod2(-/-) mice during IAV infection. In agreement with the role for DCs in priming adaptive immunity, the generation of virus-specific CD8(+) T cells and their activation and production of IFN-γ were lower in Nod2(-/-) mice. Furthermore, Nod2(-/-) DCs, when cocultured with T cells in vitro, have a lower costimulatory capacity. Thus, Nod2(-/-) DCs are unable to efficiently prime CD8(+) T cells. These findings demonstrate that Nod2 is critical for the generation of both innate and adaptive immune responses necessary for controlling IAV infection., Importance: The innate immune system is the host's first line of defense against invading pathogens and is also necessary for alerting and activating T and B cells to initiate the adaptive immune response. We demonstrate here that the innate immune receptor NOD2 is required for the production of antiviral type I interferons and the activation and survival of dendritic cells that, in turn, alert T cells to the presence of influenza A virus infection. In mice that are missing NOD2, interferon levels are lower, and the CD8(+) T cell response is impaired. As a result, the animals cannot control virus replication in their lungs as efficiently. This discovery helps us understand how the body naturally responds to virus infection and may help in the development of vaccines that use NOD2 to stimulate the CD8(+) T cell response, thus providing better protection against influenza A virus infection., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)