fbpx
Wikipedia

Herpesviridae

Herpesviridae is a large family of DNA viruses that cause infections and certain diseases in animals, including humans.[1][2][3] The members of this family are also known as herpesviruses. The family name is derived from the Greek word ἕρπειν (herpein 'to creep'), referring to spreading cutaneous lesions, usually involving blisters, seen in flares of herpes simplex 1, herpes simplex 2 and herpes zoster (shingles).[4] In 1971, the International Committee on the Taxonomy of Viruses (ICTV) established Herpesvirus as a genus with 23 viruses among four groups.[5] As of 2020, 115 species are recognized, all but one of which are in one of the three subfamilies.[6] Herpesviruses can cause both latent and lytic infections.

Herpesviridae
Virus classification
(unranked): Virus
Realm: Duplodnaviria
Kingdom: Heunggongvirae
Phylum: Peploviricota
Class: Herviviricetes
Order: Herpesvirales
Family: Orthoherpesviridae
Subfamilies and genera

See text

Nine herpesvirus types are known to primarily infect humans,[7] at least five of which are extremely widespread among most human populations, and which cause common diseases: herpes simplex 1 and 2 (HSV-1 and HSV-2, also known as HHV-1 and HHV-2; both of which can cause orolabial and genital herpes), varicella zoster (or HHV-3; the cause of chickenpox and shingles), Epstein–Barr (EBV or HHV-4; implicated in several diseases, including mononucleosis and some cancers), and human cytomegalovirus (HCMV or HHV-5). More than 90% of adults have been infected with at least one of these, and a latent form of the virus remains in almost all humans who have been infected.[8][9][10] Other human herpesviruses are human herpesvirus 6A and 6B (HHV-6A and HHV-6B), human herpesvirus 7 (HHV-7), and Kaposi's sarcoma-associated herpesvirus (KSHV, also known as HHV-8).[7]

In total, more than 130 herpesviruses are known,[11] some of them from mammals, birds, fish, reptiles, amphibians, and molluscs.[7] Among the animal herpesviruses are pseudorabies virus causing Aujeszky's disease in pigs, and bovine herpesvirus 1 causing bovine infectious rhinotracheitis and pustular vulvovaginitis.

Taxonomy edit

Additionally, the species Iguanid herpesvirus 2 is currently unassigned to a genus and subfamily.[6]

See Herpesvirales#Taxonomy for information on taxonomic history, phylogenetic research, and the nomenclatural system.

Structure edit

 
Schematic drawing of a Herpesviridae virion

All members of the Herpesviridae share a common structure; a relatively large, monopartite, double-stranded, linear DNA genome encoding 100–200 genes encased within an icosahedral protein cage (with T=16 symmetry) called the capsid, which is itself wrapped in a protein layer called the tegument containing both viral proteins and viral mRNAs and a lipid bilayer membrane called the envelope. This whole particle is known as a virion. The structural components of a typical HSV virion are the Lipid bilayer envelope, Tegument, DNA, Glycoprotein spikes and Nucleocapsid. The four-component Herpes simplex virion encompasses the double-stranded DNA genome into an icosahedral nucleocapsid. There is tegument around. Tegument contains filaments, each 7 nm wide. It is an amorphous layer with some structured regions. Finally, it is covered with a lipoprotein envelope. There are spikes made of glycoprotein protruding from each virion. These can expand the diameter of the virus to 225 nm. The diameters of virions without spikes are around 186 nm. There are at least two unglycosylated membrane proteins in the outer envelope of the virion. There are also 11 glycoproteins. These are gB, gC, gD, gE, gG, gH, gI, gJ, gK, gL and gM. Tegument contains 26 proteins. They have duties such as capsid transport to the nucleus and other organelles, activation of early gene transcription, and mRNA degradation. The icosahedral nucleocapsid is similar to that of tailed bacteriophage in the order Caudovirales. This capsid has 161 capsomers consisting of 150 hexons and 11 pentons, as well as a portal complex that allows entry and exit of DNA into the capsid.[12][13]

Life cycle edit

All herpesviruses are nuclear-replicating—the viral DNA is transcribed to mRNA within the infected cell's nucleus.[citation needed]

Infection is initiated when a viral particle contacts a cell with specific types of receptor molecules on the cell surface. Following binding of viral envelope glycoproteins to cell membrane receptors, the virion is internalized and dismantled, allowing viral DNA to migrate to the cell nucleus. Within the nucleus, replication of viral DNA and transcription of viral genes occurs.[citation needed]

During symptomatic infection, infected cells transcribe lytic viral genes. In some host cells, a small number of viral genes termed latency-associated transcript (LAT) accumulate, instead. In this fashion, the virus can persist in the cell (and thus the host) indefinitely. While primary infection is often accompanied by a self-limited period of clinical illness, long-term latency is symptom-free.[citation needed]

Chromatin dynamics regulate the transcription competency of entire herpes virus genomes. When the virus enters a cell, the cellular immune response is to protect the cell. The cell does so by wrapping the viral DNA around histones and condensing it into chromatin, causing the virus to become dormant, or latent. If cells are unsuccessful and the chromatin is loosely bundled, the viral DNA is still accessible. The viral particles can turn on their genes and replicate using cellular machinery to reactivate, starting a lytic infection.[14]

Reactivation of latent viruses has been implicated in a number of diseases (e.g. shingles, pityriasis rosea). Following activation, transcription of viral genes transitions from LAT to multiple lytic genes; these lead to enhanced replication and virus production. Often, lytic activation leads to cell death. Clinically, lytic activation is often accompanied by emergence of nonspecific symptoms, such as low-grade fever, headache, sore throat, malaise, and rash, as well as clinical signs such as swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells.[citation needed]

In animal models, local trauma and system stress have been found to induce reactivation of latent herpesvirus infection. Cellular stressors like transient interruption of protein synthesis and hypoxia are also sufficient to induce viral reactivation.[15]

Genus Subfamily Host details Tissue tropism Entry details Release details Replication site Assembly site Transmission
Iltovirus α Birds: galliform: psittacine None Cell receptor endocytosis Budding Nucleus Nucleus Oral-fecal, aerosol
Proboscivirus β Elephants None Glycoproteins Budding Nucleus Nucleus Contact
Cytomegalovirus β Humans; monkeys Epithelial mucosa, hematopoietic (blood) lineage cells Glycoproteins Budding Nucleus Nucleus Urine, saliva
Mardivirus α Chickens; turkeys; quail None Cell receptor endocytosis Budding Nucleus Nucleus Aerosol
Rhadinovirus γ Humans; mammals B-lymphocytes Glycoproteins Budding Nucleus Nucleus Sex, saliva
Macavirus γ Mammals B-lymphocytes Glycoproteins Budding Nucleus Nucleus Sex, saliva
Roseolovirus β Humans T-cells; B-cells; NK-cell; monocytes; macrophages; epithelial Glycoproteins Budding Nucleus Nucleus Respiratory contact
Simplexvirus α Humans; mammals Epithelial mucosa Cell receptor endocytosis Budding Nucleus Nucleus Sex, saliva
Scutavirus α Sea turtles None Cell receptor endocytosis Budding Nucleus Nucleus Aerosol
Varicellovirus α Mammals Epithelial mucosa Glycoproteins Budding Nucleus Nucleus Aerosol
Percavirus γ Mammals B-lymphocytes Glycoproteins Budding Nucleus Nucleus Sex, saliva
Lymphocryptovirus γ Humans; mammals B-lymphocytes Glycoproteins Budding Nucleus Nucleus Saliva
Muromegalovirus β Rodents Salivary glands Glycoproteins Budding Nucleus Nucleus Contact

Evolution edit

The three mammalian subfamilies – Alpha-, Beta- and Gamma-herpesviridae – arose approximately 180 to 220 mya.[16] The major sublineages within these subfamilies were probably generated before the mammalian radiation of 80 to 60 mya. Speciations within sublineages took place in the last 80 million years probably with a major component of cospeciation with host lineages.[citation needed]

All the currently known bird and reptile species are alphaherpesviruses. Although the branching order of the herpes viruses has not yet been resolved, because herpes viruses and their hosts tend to coevolve this is suggestive that the alphaherpesviruses may have been the earliest branch.[citation needed]

The time of origin of the genus Iltovirus has been estimated to be 200 mya while those of the mardivirus and simplex genera have been estimated to be between 150 and 100 mya.[17]

Immune system evasions edit

Herpesviruses are known for their ability to establish lifelong infections. One way this is possible is through immune evasion. Herpesviruses have many different ways of evading the immune system. One such way is by encoding a protein mimicking human interleukin 10 (hIL-10) and another is by downregulation of the major histocompatibility complex II (MHC II) in infected cells.

cmvIL-10 edit

Research conducted on cytomegalovirus (CMV) indicates that the viral human IL-10 homolog, cmvIL-10, is important in inhibiting pro-inflammatory cytokine synthesis. The cmvIL-10 protein has 27% identity with hIL-10 and only one conserved residue out of the nine amino acids that make up the functional site for cytokine synthesis inhibition on hIL-10. There is, however, much similarity in the functions of hIL-10 and cmvIL-10. Both have been shown to down regulate IFN-γ, IL-1α, GM-CSF, IL-6 and TNF-α, which are all pro-inflammatory cytokines. They have also been shown to play a role in downregulating MHC I and MHC II and up regulating HLA-G (non-classical MHC I). These two events allow for immune evasion by suppressing the cell-mediated immune response and natural killer cell response, respectively. The similarities between hIL-10 and cmvIL-10 may be explained by the fact that hIL-10 and cmvIL-10 both use the same cell surface receptor, the hIL-10 receptor. One difference in the function of hIL-10 and cmvIL-10 is that hIL-10 causes human peripheral blood mononuclear cells (PBMC) to both increase and decrease in proliferation whereas cmvIL-10 only causes a decrease in proliferation of PBMCs. This indicates that cmvIL-10 may lack the stimulatory effects that hIL-10 has on these cells.[18]

It was found that cmvIL-10 functions through phosphorylation of the Stat3 protein. It was originally thought that this phosphorylation was a result of the JAK-STAT pathway. However, despite evidence that JAK does indeed phosphorylate Stat3, its inhibition has no significant influence on cytokine synthesis inhibition. Another protein, PI3K, was also found to phosphorylate Stat3. PI3K inhibition, unlike JAK inhibition, did have a significant impact on cytokine synthesis. The difference between PI3K and JAK in Stat3 phosphorylation is that PI3K phosphorylates Stat3 on the S727 residue whereas JAK phosphorylates Stat3 on the Y705 residue. This difference in phosphorylation positions seems to be the key factor in Stat3 activation leading to inhibition of pro-inflammatory cytokine synthesis. In fact, when a PI3K inhibitor is added to cells, the cytokine synthesis levels are significantly restored. The fact that cytokine levels are not completely restored indicates there is another pathway activated by cmvIL-10 that is inhibiting cytokine system synthesis. The proposed mechanism is that cmvIL-10 activates PI3K which in turn activates PKB (Akt). PKB may then activate mTOR, which may target Stat3 for phosphorylation on the S727 residue.[19]

MHC downregulation edit

Another one of the many ways in which herpes viruses evade the immune system is by down regulation of MHC I and MHC II. This is observed in almost every human herpesvirus. Down regulation of MHC I and MHC II can come about by many different mechanisms, most causing the MHC to be absent from the cell surface. As discussed above, one way is by a viral chemokine homolog such as IL-10. Another mechanism to down regulate MHCs is to encode viral proteins that detain the newly formed MHC in the endoplasmic reticulum (ER). The MHC cannot reach the cell surface and therefore cannot activate the T cell response. The MHCs can also be targeted for destruction in the proteasome or lysosome. The ER protein TAP also plays a role in MHC down regulation. Viral proteins inhibit TAP preventing the MHC from picking up a viral antigen peptide. This prevents proper folding of the MHC and therefore the MHC does not reach the cell surface.[20]

Human herpesvirus types edit

Below are the nine distinct viruses in this family known to cause disease in humans.[21][22][23]

Human herpesvirus (HHV) classification[1][22]
Name Synonym Subfamily Primary Target Cell Syndrome Site of Latency Means of Spread
HHV‑1 Herpes simplex virus-1 (HSV-1) α (Alpha) Mucoepithelial Oral and/or genital herpes, herpetic gingivostomatitis, pharyngitis, eczema herpeticum, herpetic whitlow, herpes simplex keratitis, erythema multiforme, encephalitis, as well as other herpes simplex infections Neuron (sensory ganglia) Close contact (oral or sexually transmitted infection)
HHV-2 Herpes simplex virus-2 (HSV-2) α Mucoepithelial Oral and/or genital herpes, herpetic gingivostomatitis, pharyngitis, eczema herpeticum, herpetic whitlow, herpes simplex keratitis, erythema multiforme, Mollaret's meningitis, as well as other herpes simplex infections Neuron (sensory ganglia) Close contact (oral or sexually transmitted infection)
HHV-3 Varicella zoster virus (VZV) α Mucoepithelial Chickenpox and shingles Neuron (sensory ganglia) Respiratory and close contact (including sexually transmitted infection)
HHV-4 Epstein–Barr virus (EBV) Lymphocryptovirus γ (Gamma) B cells and epithelial cells Epstein-Barr virus-associated lymphoproliferative diseases, a large group of benign, pre-malignant, and malignant diseases including Epstein-Barr virus-positive reactive lymphoid hyperplasia, severe mosquito bite allergy, Epstein-Barr virus-positive reactive lymphoid hyperplasia, Infectious mononucleosis, Burkitt's lymphoma, Epstein–Barr virus-positive Hodgkin lymphoma, extranodal NK/T cell lymphoma, nasal type, Epstein–Barr virus-associated aggressive NK cell leukemia, CNS lymphoma in AIDS patients, post-transplant lymphoproliferative syndrome (PTLD), nasopharyngeal carcinoma, HIV-associated hairy leukoplakia, multiple sclerosis B cell Close contact, transfusions, tissue transplant, and congenital
HHV-5 Cytomegalovirus (CMV) β (Beta) Monocytes and epithelial cells Infectious mononucleosis-like syndrome,[24] retinitis Monocyte, and ? Saliva, urine, blood, breast milk
HHV-6A and 6B Roseolovirus β T cells and ? Sixth disease (roseola infantum or exanthem subitum) T cells and ? Respiratory and close contact?
HHV-7 β T cells and ? drug-induced hypersensitivity syndrome, encephalopathy, hemiconvulsion-hemiplegia-epilepsy syndrome, hepatitis infection, postinfectious myeloradiculoneuropathy, pityriasis rosea, and the reactivation of HHV-4 (EBV), leading to "mononucleosis-like illness" T cells and ? ?
HHV-8 Kaposi's sarcoma-associated herpesvirus
(KSHV), a type of Rhadinovirus
γ Lymphocyte and other cells Kaposi's sarcoma, primary effusion lymphoma, some types of multicentric Castleman's disease B cell Close contact (sexual), saliva?

Zoonotic herpesviruses edit

In addition to the herpesviruses considered endemic in humans, some viruses associated primarily with animals may infect humans. These are zoonotic infections:

Zoonotic herpesviruses
Species Type Synonym Subfamily Human Pathophysiology
Macaque monkey CeHV-1 Cercopithecine herpesvirus 1, (monkey B virus) α Very unusual, with only approximately 25 human cases reported.[25] Untreated infection is often deadly; sixteen of the 25 cases resulted in fatal encephalomyelitis. At least four cases resulted in survival with severe neurologic impairment.[25][26] Symptom awareness and early treatment are important for laboratory workers facing exposure.[27]
Mouse MuHV-4 Murid herpesvirus 68 (MHV-68) γ Zoonotic infection more common in laboratory workers handling infected mice.[28][29] ELISA tests show factor-of-four (x4) false positive results, due to antibody cross-reaction with other herpesviruses.[28]

Animal herpesviruses edit

In animal virology, the best known herpesviruses belong to the subfamily Alphaherpesvirinae. Research on pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, has pioneered animal disease control with genetically modified vaccines. PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection, and for unraveling molecular mechanisms of herpesvirus neurotropism, whereas bovine herpesvirus 1, the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis, is analyzed to elucidate molecular mechanisms of latency. The avian infectious laryngotracheitis virus is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae.[2][3]

Research edit

Research is currently ongoing into a variety of side-effect or co-conditions related to the herpesviruses. These include:

See also edit

References edit

  1. ^ a b Ryan KJ; Ray CG, eds. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
  2. ^ a b Mettenleiter; et al. (2008). "Molecular Biology of Animal Herpesviruses". Animal Viruses: Molecular Biology. Caister Academic Press. ISBN 978-1-904455-22-6. {{cite book}}: |website= ignored (help)
  3. ^ a b Sandri-Goldin RM, ed. (2006). Alpha Herpesviruses: Molecular and Cellular Biology. Caister Academic Press. ISBN 978-1-904455-09-7. {{cite book}}: |website= ignored (help)
  4. ^ Beswick TS (1962). "The Origin and the Use of the Word Herpes". Med Hist. 6 (3): 214–232. doi:10.1017/S002572730002737X. PMC 1034725. PMID 13868599.
  5. ^ Wildy P (1971). "Classification and nomenclature of viruses. First report of the International Committee on Nomenclature of Viruses". Monographs in Virology. 5: 1–81. OCLC 333944.
  6. ^ a b "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 10 May 2021.
  7. ^ a b c John Carter; Venetia Saunders (15 August 2007). Virology, Principles and Applications. John Wiley & Sons. ISBN 978-0-470-02386-0.
  8. ^ Chayavichitsilp P, Buckwalter JV, Krakowski AC, Friedlander SF (April 2009). "Herpes simplex". Pediatrics in Review. 30 (4): 119–29, quiz 130. doi:10.1542/pir.30-4-119. PMID 19339385. S2CID 34735917.
  9. ^ In the United States, as many as 15% of adults between 35 and 72 years of age have been infected. 20 April 2012 at the Wayback Machine National Center for Infectious Diseases
  10. ^ Staras SA, Dollard SC, Radford KW, Flanders WD, Pass RF, Cannon MJ (November 2006). "Seroprevalence of cytomegalovirus infection in the United States, 1988–1994". Clinical Infectious Diseases. 43 (9): 1143–51. doi:10.1086/508173. PMID 17029132.
  11. ^ Brown JC, Newcomb WW (August 2011). "Herpesvirus capsid assembly: insights from structural analysis". Current Opinion in Virology. 1 (2): 142–9. doi:10.1016/j.coviro.2011.06.003. PMC 3171831. PMID 21927635.
  12. ^ Liu, Y., Jih, J., Dai, X. et al. Cryo-EM structures of herpes simplex virus type 1 portal vertex and packaged genome. Nature 570, 257–261 (2019). https://doi.org/10.1038/s41586-019-1248-6
  13. ^ Das, D., & Hong, J. (2019). Herpesvirus Polymerase Inhibitors. In Viral Polymerases (pp. 333–356). Elsevier. https://doi.org/10.1016/B978-0-12-815422-9.00012-7
  14. ^ Hu M, Depledge DP, Flores Cortes E, Breuer J, Schang LM (November 2019). "Chromatin dynamics and the transcriptional competence of HSV-1 genomes during lytic infections". PLOS Pathogens. 15 (11): e1008076. doi:10.1371/journal.ppat.1008076. PMC 6855408. PMID 31725813.
  15. ^ Grinde B (October 2013). "Herpesviruses: latency and reactivation – viral strategies and host response". Journal of Oral Microbiology. 5 (1): 22766. doi:10.3402/jom.v5i0.22766. PMC 3809354. PMID 24167660.
  16. ^ McGeoch DJ, Cook S, Dolan A, Jamieson FE, Telford EA (March 1995). "Molecular phylogeny and evolutionary timescale for the family of mammalian herpesviruses". Journal of Molecular Biology. 247 (3): 443–58. doi:10.1006/jmbi.1995.0152. PMID 7714900.
  17. ^ McGeoch DJ, Rixon FJ, Davison AJ (April 2006). "Topics in herpesvirus genomics and evolution". Virus Research. 117 (1): 90–104. doi:10.1016/j.virusres.2006.01.002. PMID 16490275.
  18. ^ Spencer JV, Lockridge KM, Barry PA, Lin G, Tsang M, Penfold ME, Schall TJ (February 2002). "Potent immunosuppressive activities of cytomegalovirus-encoded interleukin-10". Journal of Virology. 76 (3): 1285–92. doi:10.1128/JVI.76.3.1285-1292.2002. PMC 135865. PMID 11773404.
  19. ^ Spencer JV (February 2007). "The cytomegalovirus homolog of interleukin-10 requires phosphatidylinositol 3-kinase activity for inhibition of cytokine synthesis in monocytes". Journal of Virology. 81 (4): 2083–6. doi:10.1128/JVI.01655-06. PMC 1797587. PMID 17121792.
  20. ^ Lin A, Xu H, Yan W (April 2007). "Modulation of HLA expression in human cytomegalovirus immune evasion". Cellular & Molecular Immunology. 4 (2): 91–8. PMID 17484802.
  21. ^ Adams MJ, Carstens EB (July 2012). "Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2012)". Archives of Virology. 157 (7): 1411–22. doi:10.1007/s00705-012-1299-6. PMC 7086667. PMID 22481600.
  22. ^ a b Whitley RJ (1996). Baron S; et al. (eds.). Herpesviruses. in: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1.
  23. ^ Murray PR, Rosenthal KS, Pfaller MA (2005). Medical Microbiology (5th ed.). Elsevier Mosby. ISBN 978-0-323-03303-9.
  24. ^ Bottieau E, Clerinx J, Van den Enden E, Van Esbroeck M, Colebunders R, Van Gompel A, Van den Ende J (2006). "Infectious mononucleosis-like syndromes in febrile travelers returning from the tropics". Journal of Travel Medicine. 13 (4): 191–7. doi:10.1111/j.1708-8305.2006.00049.x. PMID 16884400.
  25. ^ a b Weigler BJ (February 1992). "Biology of B virus in macaque and human hosts: a review". Clinical Infectious Diseases. 14 (2): 555–67. doi:10.1093/clinids/14.2.555. PMID 1313312.
  26. ^ Huff JL, Barry PA (February 2003). "B-virus (Cercopithecine herpesvirus 1) infection in humans and macaques: potential for zoonotic disease". Emerging Infectious Diseases. 9 (2): 246–50. doi:10.3201/eid0902.020272. PMC 2901951. PMID 12603998.
  27. ^ Herpes-B Fact Sheet 6 January 2008 at the Wayback Machine
  28. ^ a b Hricová M, Mistríková J (2007). "Murine gammaherpesvirus 68 serum antibodies in general human population". Acta Virologica. 51 (4): 283–7. PMID 18197737.
  29. ^ Wang Y, Tibbetts SA, Krug LT (29 September 2021). "Conquering the Host: Determinants of Pathogenesis Learned from Murine Gammaherpesvirus 68". Annual Review of Virology. 8 (1): 349–371. doi:10.1146/annurev-virology-011921-082615. ISSN 2327-056X. PMC 9153731. PMID 34586873.

External links edit

  • Viralzone: Herpesviridae
  • Animal viruses
  • Article on Cercopithecine herpesvirus
  • National B Virus Resource Center
  • Pityriasis Rosea overview
  • Herpes simplex: Host viral protein interactions.A database of Host/HSV-1 interactions
  • Virus Pathogen Database and Analysis Resource (ViPR): Herpesviridae

herpesviridae, large, family, viruses, that, cause, infections, certain, diseases, animals, including, humans, members, this, family, also, known, herpesviruses, family, name, derived, from, greek, word, ἕρπειν, herpein, creep, referring, spreading, cutaneous,. Herpesviridae is a large family of DNA viruses that cause infections and certain diseases in animals including humans 1 2 3 The members of this family are also known as herpesviruses The family name is derived from the Greek word ἕrpein herpein to creep referring to spreading cutaneous lesions usually involving blisters seen in flares of herpes simplex 1 herpes simplex 2 and herpes zoster shingles 4 In 1971 the International Committee on the Taxonomy of Viruses ICTV established Herpesvirus as a genus with 23 viruses among four groups 5 As of 2020 115 species are recognized all but one of which are in one of the three subfamilies 6 Herpesviruses can cause both latent and lytic infections HerpesviridaeVirus classification unranked VirusRealm DuplodnaviriaKingdom HeunggongviraePhylum PeploviricotaClass HerviviricetesOrder HerpesviralesFamily OrthoherpesviridaeSubfamilies and generaSee textNine herpesvirus types are known to primarily infect humans 7 at least five of which are extremely widespread among most human populations and which cause common diseases herpes simplex 1 and 2 HSV 1 and HSV 2 also known as HHV 1 and HHV 2 both of which can cause orolabial and genital herpes varicella zoster or HHV 3 the cause of chickenpox and shingles Epstein Barr EBV or HHV 4 implicated in several diseases including mononucleosis and some cancers and human cytomegalovirus HCMV or HHV 5 More than 90 of adults have been infected with at least one of these and a latent form of the virus remains in almost all humans who have been infected 8 9 10 Other human herpesviruses are human herpesvirus 6A and 6B HHV 6A and HHV 6B human herpesvirus 7 HHV 7 and Kaposi s sarcoma associated herpesvirus KSHV also known as HHV 8 7 In total more than 130 herpesviruses are known 11 some of them from mammals birds fish reptiles amphibians and molluscs 7 Among the animal herpesviruses are pseudorabies virus causing Aujeszky s disease in pigs and bovine herpesvirus 1 causing bovine infectious rhinotracheitis and pustular vulvovaginitis Contents 1 Taxonomy 2 Structure 3 Life cycle 4 Evolution 5 Immune system evasions 5 1 cmvIL 10 5 2 MHC downregulation 6 Human herpesvirus types 6 1 Zoonotic herpesviruses 7 Animal herpesviruses 8 Research 9 See also 10 References 11 External linksTaxonomy editSubfamily Alphaherpesvirinae Iltovirus Mardivirus Scutavirus Simplexvirus Varicellovirus Subfamily Betaherpesvirinae Cytomegalovirus Muromegalovirus Proboscivirus Quwivirus Roseolovirus Subfamily Gammaherpesvirinae Bossavirus Lymphocryptovirus Macavirus Manticavirus Patagivirus Percavirus RhadinovirusAdditionally the species Iguanid herpesvirus 2 is currently unassigned to a genus and subfamily 6 See Herpesvirales Taxonomy for information on taxonomic history phylogenetic research and the nomenclatural system Structure edit nbsp Schematic drawing of a Herpesviridae virionAll members of the Herpesviridae share a common structure a relatively large monopartite double stranded linear DNA genome encoding 100 200 genes encased within an icosahedral protein cage with T 16 symmetry called the capsid which is itself wrapped in a protein layer called the tegument containing both viral proteins and viral mRNAs and a lipid bilayer membrane called the envelope This whole particle is known as a virion The structural components of a typical HSV virion are the Lipid bilayer envelope Tegument DNA Glycoprotein spikes and Nucleocapsid The four component Herpes simplex virion encompasses the double stranded DNA genome into an icosahedral nucleocapsid There is tegument around Tegument contains filaments each 7 nm wide It is an amorphous layer with some structured regions Finally it is covered with a lipoprotein envelope There are spikes made of glycoprotein protruding from each virion These can expand the diameter of the virus to 225 nm The diameters of virions without spikes are around 186 nm There are at least two unglycosylated membrane proteins in the outer envelope of the virion There are also 11 glycoproteins These are gB gC gD gE gG gH gI gJ gK gL and gM Tegument contains 26 proteins They have duties such as capsid transport to the nucleus and other organelles activation of early gene transcription and mRNA degradation The icosahedral nucleocapsid is similar to that of tailed bacteriophage in the order Caudovirales This capsid has 161 capsomers consisting of 150 hexons and 11 pentons as well as a portal complex that allows entry and exit of DNA into the capsid 12 13 Life cycle editAll herpesviruses are nuclear replicating the viral DNA is transcribed to mRNA within the infected cell s nucleus citation needed Infection is initiated when a viral particle contacts a cell with specific types of receptor molecules on the cell surface Following binding of viral envelope glycoproteins to cell membrane receptors the virion is internalized and dismantled allowing viral DNA to migrate to the cell nucleus Within the nucleus replication of viral DNA and transcription of viral genes occurs citation needed During symptomatic infection infected cells transcribe lytic viral genes In some host cells a small number of viral genes termed latency associated transcript LAT accumulate instead In this fashion the virus can persist in the cell and thus the host indefinitely While primary infection is often accompanied by a self limited period of clinical illness long term latency is symptom free citation needed Chromatin dynamics regulate the transcription competency of entire herpes virus genomes When the virus enters a cell the cellular immune response is to protect the cell The cell does so by wrapping the viral DNA around histones and condensing it into chromatin causing the virus to become dormant or latent If cells are unsuccessful and the chromatin is loosely bundled the viral DNA is still accessible The viral particles can turn on their genes and replicate using cellular machinery to reactivate starting a lytic infection 14 Reactivation of latent viruses has been implicated in a number of diseases e g shingles pityriasis rosea Following activation transcription of viral genes transitions from LAT to multiple lytic genes these lead to enhanced replication and virus production Often lytic activation leads to cell death Clinically lytic activation is often accompanied by emergence of nonspecific symptoms such as low grade fever headache sore throat malaise and rash as well as clinical signs such as swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells citation needed In animal models local trauma and system stress have been found to induce reactivation of latent herpesvirus infection Cellular stressors like transient interruption of protein synthesis and hypoxia are also sufficient to induce viral reactivation 15 Genus Subfamily Host details Tissue tropism Entry details Release details Replication site Assembly site TransmissionIltovirus a Birds galliform psittacine None Cell receptor endocytosis Budding Nucleus Nucleus Oral fecal aerosolProboscivirus b Elephants None Glycoproteins Budding Nucleus Nucleus ContactCytomegalovirus b Humans monkeys Epithelial mucosa hematopoietic blood lineage cells Glycoproteins Budding Nucleus Nucleus Urine salivaMardivirus a Chickens turkeys quail None Cell receptor endocytosis Budding Nucleus Nucleus AerosolRhadinovirus g Humans mammals B lymphocytes Glycoproteins Budding Nucleus Nucleus Sex salivaMacavirus g Mammals B lymphocytes Glycoproteins Budding Nucleus Nucleus Sex salivaRoseolovirus b Humans T cells B cells NK cell monocytes macrophages epithelial Glycoproteins Budding Nucleus Nucleus Respiratory contactSimplexvirus a Humans mammals Epithelial mucosa Cell receptor endocytosis Budding Nucleus Nucleus Sex salivaScutavirus a Sea turtles None Cell receptor endocytosis Budding Nucleus Nucleus AerosolVaricellovirus a Mammals Epithelial mucosa Glycoproteins Budding Nucleus Nucleus AerosolPercavirus g Mammals B lymphocytes Glycoproteins Budding Nucleus Nucleus Sex salivaLymphocryptovirus g Humans mammals B lymphocytes Glycoproteins Budding Nucleus Nucleus SalivaMuromegalovirus b Rodents Salivary glands Glycoproteins Budding Nucleus Nucleus ContactEvolution editThe three mammalian subfamilies Alpha Beta and Gamma herpesviridae arose approximately 180 to 220 mya 16 The major sublineages within these subfamilies were probably generated before the mammalian radiation of 80 to 60 mya Speciations within sublineages took place in the last 80 million years probably with a major component of cospeciation with host lineages citation needed All the currently known bird and reptile species are alphaherpesviruses Although the branching order of the herpes viruses has not yet been resolved because herpes viruses and their hosts tend to coevolve this is suggestive that the alphaherpesviruses may have been the earliest branch citation needed The time of origin of the genus Iltovirus has been estimated to be 200 mya while those of the mardivirus and simplex genera have been estimated to be between 150 and 100 mya 17 Immune system evasions editThis section is missing information about latency mechanisms beyond CMV e g HSV LAT and ICP 47 whether there is a common mechanism in the family Please expand the section to include this information Further details may exist on the talk page November 2021 Herpesviruses are known for their ability to establish lifelong infections One way this is possible is through immune evasion Herpesviruses have many different ways of evading the immune system One such way is by encoding a protein mimicking human interleukin 10 hIL 10 and another is by downregulation of the major histocompatibility complex II MHC II in infected cells cmvIL 10 edit Research conducted on cytomegalovirus CMV indicates that the viral human IL 10 homolog cmvIL 10 is important in inhibiting pro inflammatory cytokine synthesis The cmvIL 10 protein has 27 identity with hIL 10 and only one conserved residue out of the nine amino acids that make up the functional site for cytokine synthesis inhibition on hIL 10 There is however much similarity in the functions of hIL 10 and cmvIL 10 Both have been shown to down regulate IFN g IL 1a GM CSF IL 6 and TNF a which are all pro inflammatory cytokines They have also been shown to play a role in downregulating MHC I and MHC II and up regulating HLA G non classical MHC I These two events allow for immune evasion by suppressing the cell mediated immune response and natural killer cell response respectively The similarities between hIL 10 and cmvIL 10 may be explained by the fact that hIL 10 and cmvIL 10 both use the same cell surface receptor the hIL 10 receptor One difference in the function of hIL 10 and cmvIL 10 is that hIL 10 causes human peripheral blood mononuclear cells PBMC to both increase and decrease in proliferation whereas cmvIL 10 only causes a decrease in proliferation of PBMCs This indicates that cmvIL 10 may lack the stimulatory effects that hIL 10 has on these cells 18 It was found that cmvIL 10 functions through phosphorylation of the Stat3 protein It was originally thought that this phosphorylation was a result of the JAK STAT pathway However despite evidence that JAK does indeed phosphorylate Stat3 its inhibition has no significant influence on cytokine synthesis inhibition Another protein PI3K was also found to phosphorylate Stat3 PI3K inhibition unlike JAK inhibition did have a significant impact on cytokine synthesis The difference between PI3K and JAK in Stat3 phosphorylation is that PI3K phosphorylates Stat3 on the S727 residue whereas JAK phosphorylates Stat3 on the Y705 residue This difference in phosphorylation positions seems to be the key factor in Stat3 activation leading to inhibition of pro inflammatory cytokine synthesis In fact when a PI3K inhibitor is added to cells the cytokine synthesis levels are significantly restored The fact that cytokine levels are not completely restored indicates there is another pathway activated by cmvIL 10 that is inhibiting cytokine system synthesis The proposed mechanism is that cmvIL 10 activates PI3K which in turn activates PKB Akt PKB may then activate mTOR which may target Stat3 for phosphorylation on the S727 residue 19 MHC downregulation edit Another one of the many ways in which herpes viruses evade the immune system is by down regulation of MHC I and MHC II This is observed in almost every human herpesvirus Down regulation of MHC I and MHC II can come about by many different mechanisms most causing the MHC to be absent from the cell surface As discussed above one way is by a viral chemokine homolog such as IL 10 Another mechanism to down regulate MHCs is to encode viral proteins that detain the newly formed MHC in the endoplasmic reticulum ER The MHC cannot reach the cell surface and therefore cannot activate the T cell response The MHCs can also be targeted for destruction in the proteasome or lysosome The ER protein TAP also plays a role in MHC down regulation Viral proteins inhibit TAP preventing the MHC from picking up a viral antigen peptide This prevents proper folding of the MHC and therefore the MHC does not reach the cell surface 20 Human herpesvirus types editBelow are the nine distinct viruses in this family known to cause disease in humans 21 22 23 Human herpesvirus HHV classification 1 22 Name Synonym Subfamily Primary Target Cell Syndrome Site of Latency Means of SpreadHHV 1 Herpes simplex virus 1 HSV 1 a Alpha Mucoepithelial Oral and or genital herpes herpetic gingivostomatitis pharyngitis eczema herpeticum herpetic whitlow herpes simplex keratitis erythema multiforme encephalitis as well as other herpes simplex infections Neuron sensory ganglia Close contact oral or sexually transmitted infection HHV 2 Herpes simplex virus 2 HSV 2 a Mucoepithelial Oral and or genital herpes herpetic gingivostomatitis pharyngitis eczema herpeticum herpetic whitlow herpes simplex keratitis erythema multiforme Mollaret s meningitis as well as other herpes simplex infections Neuron sensory ganglia Close contact oral or sexually transmitted infection HHV 3 Varicella zoster virus VZV a Mucoepithelial Chickenpox and shingles Neuron sensory ganglia Respiratory and close contact including sexually transmitted infection HHV 4 Epstein Barr virus EBV Lymphocryptovirus g Gamma B cells and epithelial cells Epstein Barr virus associated lymphoproliferative diseases a large group of benign pre malignant and malignant diseases including Epstein Barr virus positive reactive lymphoid hyperplasia severe mosquito bite allergy Epstein Barr virus positive reactive lymphoid hyperplasia Infectious mononucleosis Burkitt s lymphoma Epstein Barr virus positive Hodgkin lymphoma extranodal NK T cell lymphoma nasal type Epstein Barr virus associated aggressive NK cell leukemia CNS lymphoma in AIDS patients post transplant lymphoproliferative syndrome PTLD nasopharyngeal carcinoma HIV associated hairy leukoplakia multiple sclerosis B cell Close contact transfusions tissue transplant and congenitalHHV 5 Cytomegalovirus CMV b Beta Monocytes and epithelial cells Infectious mononucleosis like syndrome 24 retinitis Monocyte and Saliva urine blood breast milkHHV 6A and 6B Roseolovirus b T cells and Sixth disease roseola infantum or exanthem subitum T cells and Respiratory and close contact HHV 7 b T cells and drug induced hypersensitivity syndrome encephalopathy hemiconvulsion hemiplegia epilepsy syndrome hepatitis infection postinfectious myeloradiculoneuropathy pityriasis rosea and the reactivation of HHV 4 EBV leading to mononucleosis like illness T cells and HHV 8 Kaposi s sarcoma associated herpesvirus KSHV a type of Rhadinovirus g Lymphocyte and other cells Kaposi s sarcoma primary effusion lymphoma some types of multicentric Castleman s disease B cell Close contact sexual saliva Zoonotic herpesviruses edit In addition to the herpesviruses considered endemic in humans some viruses associated primarily with animals may infect humans These are zoonotic infections Zoonotic herpesviruses Species Type Synonym Subfamily Human PathophysiologyMacaque monkey CeHV 1 Cercopithecine herpesvirus 1 monkey B virus a Very unusual with only approximately 25 human cases reported 25 Untreated infection is often deadly sixteen of the 25 cases resulted in fatal encephalomyelitis At least four cases resulted in survival with severe neurologic impairment 25 26 Symptom awareness and early treatment are important for laboratory workers facing exposure 27 Mouse MuHV 4 Murid herpesvirus 68 MHV 68 g Zoonotic infection more common in laboratory workers handling infected mice 28 29 ELISA tests show factor of four x4 false positive results due to antibody cross reaction with other herpesviruses 28 Animal herpesviruses editIn animal virology the best known herpesviruses belong to the subfamily Alphaherpesvirinae Research on pseudorabies virus PrV the causative agent of Aujeszky s disease in pigs has pioneered animal disease control with genetically modified vaccines PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection and for unraveling molecular mechanisms of herpesvirus neurotropism whereas bovine herpesvirus 1 the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis is analyzed to elucidate molecular mechanisms of latency The avian infectious laryngotracheitis virus is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae 2 3 Research editMain article Herpes simplex research Research is currently ongoing into a variety of side effect or co conditions related to the herpesviruses These include Alzheimer s disease atherosclerosis cholangiocarcinoma chronic fatigue syndrome Crohn s disease dysautonomia fibromyalgia Irritable bowel syndrome labile hypertension lupus Meniere s disease multiple sclerosis pancreatic cancer pancreatitis pityriasis rosea Type II DiabetesSee also editAcciptrid herpesvirus 1 Agua Preta virus a potential herpesvirusReferences edit a b Ryan KJ Ray CG eds 2004 Sherris Medical Microbiology 4th ed McGraw Hill ISBN 0 8385 8529 9 a b Mettenleiter et al 2008 Molecular Biology of Animal Herpesviruses Animal Viruses Molecular Biology Caister Academic Press ISBN 978 1 904455 22 6 a href Template Cite book html title Template Cite book cite book a website ignored help a b Sandri Goldin RM ed 2006 Alpha Herpesviruses Molecular and Cellular Biology Caister Academic Press ISBN 978 1 904455 09 7 a href Template Cite book html title Template Cite book cite book a website ignored help Beswick TS 1962 The Origin and the Use of the Word Herpes Med Hist 6 3 214 232 doi 10 1017 S002572730002737X PMC 1034725 PMID 13868599 Wildy P 1971 Classification and nomenclature of viruses First report of the International Committee on Nomenclature of Viruses Monographs in Virology 5 1 81 OCLC 333944 a b Virus Taxonomy 2020 Release International Committee on Taxonomy of Viruses ICTV March 2021 Retrieved 10 May 2021 a b c John Carter Venetia Saunders 15 August 2007 Virology Principles and Applications John Wiley amp Sons ISBN 978 0 470 02386 0 Chayavichitsilp P Buckwalter JV Krakowski AC Friedlander SF April 2009 Herpes simplex Pediatrics in Review 30 4 119 29 quiz 130 doi 10 1542 pir 30 4 119 PMID 19339385 S2CID 34735917 In the United States as many as 15 of adults between 35 and 72 years of age have been infected Archived 20 April 2012 at the Wayback Machine National Center for Infectious Diseases Staras SA Dollard SC Radford KW Flanders WD Pass RF Cannon MJ November 2006 Seroprevalence of cytomegalovirus infection in the United States 1988 1994 Clinical Infectious Diseases 43 9 1143 51 doi 10 1086 508173 PMID 17029132 Brown JC Newcomb WW August 2011 Herpesvirus capsid assembly insights from structural analysis Current Opinion in Virology 1 2 142 9 doi 10 1016 j coviro 2011 06 003 PMC 3171831 PMID 21927635 Liu Y Jih J Dai X et al Cryo EM structures of herpes simplex virus type 1 portal vertex and packaged genome Nature 570 257 261 2019 https doi org 10 1038 s41586 019 1248 6 Das D amp Hong J 2019 Herpesvirus Polymerase Inhibitors In Viral Polymerases pp 333 356 Elsevier https doi org 10 1016 B978 0 12 815422 9 00012 7 Hu M Depledge DP Flores Cortes E Breuer J Schang LM November 2019 Chromatin dynamics and the transcriptional competence of HSV 1 genomes during lytic infections PLOS Pathogens 15 11 e1008076 doi 10 1371 journal ppat 1008076 PMC 6855408 PMID 31725813 Grinde B October 2013 Herpesviruses latency and reactivation viral strategies and host response Journal of Oral Microbiology 5 1 22766 doi 10 3402 jom v5i0 22766 PMC 3809354 PMID 24167660 McGeoch DJ Cook S Dolan A Jamieson FE Telford EA March 1995 Molecular phylogeny and evolutionary timescale for the family of mammalian herpesviruses Journal of Molecular Biology 247 3 443 58 doi 10 1006 jmbi 1995 0152 PMID 7714900 McGeoch DJ Rixon FJ Davison AJ April 2006 Topics in herpesvirus genomics and evolution Virus Research 117 1 90 104 doi 10 1016 j virusres 2006 01 002 PMID 16490275 Spencer JV Lockridge KM Barry PA Lin G Tsang M Penfold ME Schall TJ February 2002 Potent immunosuppressive activities of cytomegalovirus encoded interleukin 10 Journal of Virology 76 3 1285 92 doi 10 1128 JVI 76 3 1285 1292 2002 PMC 135865 PMID 11773404 Spencer JV February 2007 The cytomegalovirus homolog of interleukin 10 requires phosphatidylinositol 3 kinase activity for inhibition of cytokine synthesis in monocytes Journal of Virology 81 4 2083 6 doi 10 1128 JVI 01655 06 PMC 1797587 PMID 17121792 Lin A Xu H Yan W April 2007 Modulation of HLA expression in human cytomegalovirus immune evasion Cellular amp Molecular Immunology 4 2 91 8 PMID 17484802 Adams MJ Carstens EB July 2012 Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses 2012 Archives of Virology 157 7 1411 22 doi 10 1007 s00705 012 1299 6 PMC 7086667 PMID 22481600 a b Whitley RJ 1996 Baron S et al eds Herpesviruses in Baron s Medical Microbiology 4th ed Univ of Texas Medical Branch ISBN 0 9631172 1 1 Murray PR Rosenthal KS Pfaller MA 2005 Medical Microbiology 5th ed Elsevier Mosby ISBN 978 0 323 03303 9 Bottieau E Clerinx J Van den Enden E Van Esbroeck M Colebunders R Van Gompel A Van den Ende J 2006 Infectious mononucleosis like syndromes in febrile travelers returning from the tropics Journal of Travel Medicine 13 4 191 7 doi 10 1111 j 1708 8305 2006 00049 x PMID 16884400 a b Weigler BJ February 1992 Biology of B virus in macaque and human hosts a review Clinical Infectious Diseases 14 2 555 67 doi 10 1093 clinids 14 2 555 PMID 1313312 Huff JL Barry PA February 2003 B virus Cercopithecine herpesvirus 1 infection in humans and macaques potential for zoonotic disease Emerging Infectious Diseases 9 2 246 50 doi 10 3201 eid0902 020272 PMC 2901951 PMID 12603998 Herpes B Fact Sheet Archived 6 January 2008 at the Wayback Machine a b Hricova M Mistrikova J 2007 Murine gammaherpesvirus 68 serum antibodies in general human population Acta Virologica 51 4 283 7 PMID 18197737 Wang Y Tibbetts SA Krug LT 29 September 2021 Conquering the Host Determinants of Pathogenesis Learned from Murine Gammaherpesvirus 68 Annual Review of Virology 8 1 349 371 doi 10 1146 annurev virology 011921 082615 ISSN 2327 056X PMC 9153731 PMID 34586873 External links edit nbsp Wikispecies has information related to Herpesviridae nbsp Wikimedia Commons has media related to Herpesviridae ICTV International Committee on Taxonomy of Viruses official site Viralzone Herpesviridae Animal viruses Article on Cercopithecine herpesvirus National B Virus Resource Center Pityriasis Rosea overview Herpes simplex Host viral protein interactions A database of Host HSV 1 interactions Virus Pathogen Database and Analysis Resource ViPR Herpesviridae Retrieved from https en wikipedia org w index php title Herpesviridae amp oldid 1207256563, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.