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The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
The replication process in the RNA tumor viruses is unique. The single-stranded viral RNA template is used to produce an initial DNA-RNA hybrid, which is then converted by DNA polymerase into a double stranded DNA linear intermediate. The DNA intermediate integrates into the host cell DNA and is referred to as a “provirus.” The provirus is transcribed into both viral messenger and viral genomic RNA. The RNA viruses containing reverse transcriptase were named the Retroviridae (Table 16.1) in recognition of the retrograde flow of genetic information from RNA into DNA. Retroviruses are known to infect a wide variety of animals, including humans, and are associated with certain types of cancer. They may also induce immunosuppressive or immune-mediated diseases, or may exist as stable members of the host germ line.
Human immunodeficiency virus (HIV)
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Richard Basilan, William Salzer
HIV belongs to the family of human retroviruses (Retroviridae) and the subfamily of lentiviruses. HIV-1 is the predominant cause of HIV disease in the world. HIV-2, which can also cause AIDS, is closely related to simian immunodeficiency virus and is largely confined to West Africa, although occasional cases occur worldwide. The HIV virion is an icosahedral structure containing numerous external spikes formed by the two major envelope proteins, the external gp120, and the transmembrane gp41. The virion attaches via gp120 to cells expressing the CD4 molecule, which acts as the cell receptor for the virus. The CD4 molecule is expressed mainly in a subset of T lymphocytes responsible for helper function in the immune system, but can also be found on the surface of monocytes/macrophages and dendritic/Langerhans cells (13). A conformational change then occurs in the gp120 molecule, allowing it to bind to one of two cellular coreceptors (CCR5 or CXCR4). Binding is followed by insertion of viral gp41 into the CD4 cell, resulting in membrane fusion followed by release of the viral core into the cell cytoplasm.
Viruses and Antiviral Agents
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Richard B. Townsley, Camille A. Huser, Chris Hansell
One large class of single-stranded RNA viruses are the Retroviridae, or retroviruses, which contain the enzyme reverse transcriptase, allowing them to synthesize double-stranded DNA from their RNA genome. One such virus is the human immunodeficiency virus (HIV), which is discussed in Chapter 23.
Tracing the recent updates on vaccination approaches and significant adjuvants being developed against HIV
Published in Expert Review of Anti-infective Therapy, 2023
Shiza Malik, Khalid Muhammad, Sanaa Masood Aslam, Yasir Waheed
A brief description of the biology of this virus includes the fact that HIV-1 belongs to the family of Retroviridae which were shown to beis the disease-causing agents of AIDS in 1983 [4]. Retroviridae are RNA viruses [5]. Viruses in this family are classified in two subfamilies and HIV-1 belongs to a genus designated as Lentivirus. HIV-1 is composed of two copies of single stranded RNA. RNA strands encode structural, regulatory, and accessory proteins that complement virus replication [5]. The virus brings about infection by binding to cell-surface enveloped glycoproteins [4]. The immune cells that get directly infected by HIV-1 are T-cells, macrophages, dendritic cells, and a few others [6] . HIV is responsible for the most deadly disease of humankind; for this reason effective vaccines and anti-viral drugs could be the only options for clinicians and researchers to cope with the harms of HIV/AIDS [7,8].
Recent advances in nanoformulation development of Ritonavir, a key protease inhibitor used in the treatment of HIV-AIDS
Published in Expert Opinion on Drug Delivery, 2022
Srinivas Reddy Jitta, Navya Ajitkumar Bhaskaran, Shirleen Miriam Marques, Lalit Kumar
Acquired immunodeficiency syndrome (AIDS) is one of the serious healthcare problems causing significant mortality and morbidity globally [1]. AIDS was first recognized in 1981 and is caused by the human immunodeficiency virus (HIV) [2]. HIV is a retrovirus belonging to the genus Lentivirus subfamily of Orthoretrovirinae within the family of Retroviridae. According to global HIV and AIDS statistics 2020, approximately 37.6 million people were living with HIV at the end of 2020. In 2020, 690,000 people died because of HIV-related issues, and 1.5 million were newly infected. As per the statistics, only 27.4 million people received antiretroviral therapy in 2020. Only 53% of children living with HIV received antiretroviral therapy (ART) in 2020. WHO has recommended that all people infected with HIV, including children, adolescents, adults, and pregnant and breastfeeding women, be provided with lifelong ART treatment irrespective of clinical status or CD4 cell count [3]. Even though the death rate fell in the past two decades, people on HIV treatment are still suffering from several adverse effects of antiretroviral therapy. It is one of the main reasons for the lack of adherence to the treatment by HIV patients.
Retroviruses in the pathogenesis of systemic lupus erythematosus: Are they potential therapeutic targets?
Published in Autoimmunity, 2020
Rossella Talotta, Fabiola Atzeni, Magdalena Janina Laska
Retroviruses belong to the family of Retroviridae. This family is further subdivided in two subfamilies: the Orthoretrovirinae and the Spumaretrovirinae [41], distinguished on the basis of their biologic features. The Orthoretrovirinae subfamily encloses six genera (alpha-, beta-, delta-, epsilon- and gamma-retroviruses and lentiviruses), consisting of simple and complex viruses according to the coding domains present in their genome; of note, five out of the six genera display oncogenic properties [42]. The coding domains gag, pol, pro and env are present in all retroviruses and preside to the synthesis of core and envelope proteins and enzymes. Additional domains, generated by alternative splicing, are present in complex retroviruses, and code for regulatory proteins, like Tat and Rev, whose role is to enhance viral gene expression [43].