# Muhammed Ömercan Özleyen **Herpes Simplex Viruses** ''Temel, Klinik ve Tanısal Tıbbi Viroloji by PROF. DR. MUSTAFA ALTINDİŞ''


# Herpes Simplex Vİruses
Herpes viruses are common in nature. Although there are many members, eight herpes viruses divided into three subfamilies that share common genetic and antigenic structures and cause different diseases in humans have been identified. These viruses are herpes simplex virus (HSV) type 1 and type 2, varicella-zoester virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpes virus-6 (HHV-6) , human herpes virus-7 (HHV-7) and human herpes virus-8 (HHV-8) are called human human herpes viruses.
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# Viral Features

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Figure 1. Viral Features of HSV (Herpes Simplex Virus: Structure, Clinical Feature, Lab Diagnosis
April 20, 2010 Acharya Tankeshwar)

Herpesviruses are large, enveloped viruses containing double-stranded DNA, with icosahedral capsid symmetry. Viral DNA has long and short regions. Variations of these regions are responsible for isometric forms and mutations.
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Enveloped virus contains lipid, glycoprotein and polyamine structures on its surface. The glycoprotein structure is antigenic and is responsible for the immune response and the differentiation of viruses. Between the capsid and the membrane, there is an asymmetrically located part called the tegument(Figure 1.).
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# Classification of Herpes Simplex Viruses
Viruses in the Herpes Virus family are examined in three subfamilies according to their biological characteristics. There are viruses in the Alphaherpesvirinae subfamily that cause significant damage to the host cell and can reproduce in many tissues. These viruses remain latent in the sensory ganglia and have a short reproductive cycle.
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HSV-1, HSV-2 and VZV are members of this group.The Betaherpesivinae subfamily are viruses with a slower reproductive cycle and limited host spectrum. Members of this subgroup enlarge cells during their reproduction. They remain latent in the salivary gland and kidneys. CMV, HHV-6 and HHV-7 are members of this subfamily.
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The Gammaherpesvirinae subfamily includes EBV, which remains latent by infecting lymphoid cells, and HHV-8, the so-called Kaposi's Sarcoma-associated virus.
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Figure 2. Classfication of Herpes Simplex Viruses (Viral G-quadruplexes: New frontiers in virus pathogenesis and antiviral therapy
May 2020Annual Reports in Medicinal Chemistry 54 Emanuela RuggieroSara,RichterSara N Richter)
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# Replication of Herpes Simplex Virus 1 and 2

Herpes simplex virus enters the cell by fusion by binding with envelope glycoproteins to glycosaminoglycans on the host cell surface. After the fusion process, transition from the cytoplasm to the nucleus via the nuclear pore and peeling from the sheath occurs. After the capsid is stripped, the viral DNA goes to the host cell nucleus and virus-specific synthesis steps take place.
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VP16 complexes with some cellular proteins and initiates the earliest gene expression. After the earliest gene expression,
α proteins are synthesized. These proteins lead to the expression of early genes and translation of beta proteins occurs.
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Viral replication begins, and then late genes lead to the formation of gamma proteins. These enzymes are a good target for antiviral agents. The newly synthesized viral DNA is packaged in nucleocapsids in the cell nucleus. The maturation phase occurs by budding of nucleocapsids from the inner nuclear membrane. Enveloped virus particles are transferred to the cell surface by vesicular movements.(Figure 2)
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Figure 2. Replication of Herpes Simplex Virus(https://www.slideshare.net/DeepakKumarGupta2/herpes-virus-53467629)
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