ABSTRACT
Virus invasion activates the host's innate immune response, inducing the production of numerous cytokines and interferons to eliminate pathogens. Except for viral DNA/RNA, viral proteins are also targets of pattern recognition receptors. Membrane-bound receptors such as Toll-like receptor (TLR)1, TLR2, TLR4, TLR6, and TLR10 relate to the recognition of viral proteins. Distinct TLRs perform both protective and detrimental roles for a specific virus. Here, we review viral proteins serving as pathogen-associated molecular patterns and their corresponding TLRs. These viruses are all enveloped, including respiratory syncytial virus, hepatitis C virus, measles virus, herpesvirus human immunodeficiency virus, and coronavirus, and can encode proteins to activate innate immunity in a TLR-dependent way. The TLR-viral protein relationship plays an important role in innate immunity activation. A detailed understanding of their pathways contributes to a novel direction for vaccine development.
Subject(s)
Immunity, Innate , Pathogen-Associated Molecular Pattern Molecules/metabolism , Toll-Like Receptors/immunology , Toll-Like Receptors/metabolism , Viral Proteins/metabolism , Virus Diseases/immunology , Viruses/immunology , Animals , HIV/immunology , HIV/metabolism , HIV/pathogenicity , Hepacivirus/immunology , Hepacivirus/metabolism , Hepacivirus/pathogenicity , Herpesviridae/immunology , Herpesviridae/metabolism , Herpesviridae/pathogenicity , Humans , Measles virus/immunology , Measles virus/metabolism , Measles virus/pathogenicity , Pathogen-Associated Molecular Pattern Molecules/chemistry , Respiratory Syncytial Viruses/immunology , Respiratory Syncytial Viruses/metabolism , Respiratory Syncytial Viruses/pathogenicity , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Viral Proteins/chemistry , Virus Diseases/virology , Viruses/metabolism , Viruses/pathogenicityABSTRACT
Virus-induced infections of the central nervous system (CNS) are among the most serious problems in public health and can be associated with high rates of morbidity and mortality, mainly in low- and middle-income countries, where these manifestations have been neglected. Typically, herpes simplex virus 1 and 2, varicella-zoster, and enterovirus are responsible for a high number of cases in immunocompetent hosts, whereas other herpesviruses (for example, cytomegalovirus) are the most common in immunocompromised individuals. Arboviruses have also been associated with outbreaks with a high burden of neurological disorders, such as the Zika virus epidemic in Brazil. There is a current lack of understanding in Brazil about the most common viruses involved in CNS infections. In this review, we briefly summarize the most recent studies and findings associated with the CNS, in addition to epidemiological data that provide extensive information on the circulation and diversity of the most common neuro-invasive viruses in Brazil. We also highlight important aspects of the prion-associated diseases. This review provides readers with better knowledge of virus-associated CNS infections. A deeper understanding of these infections will support the improvement of the current surveillance strategies to allow the timely monitoring of the emergence/re-emergence of neurotropic viruses.