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Retroviruses. Human immunodeficiency virus. Oncogenic viruses. Mechanisms of viral oncogenesis

Retroviruses. Human immunodeficiency virus. Oncogenic viruses. Mechanisms of viral oncogenesis. Classification. Family Retroviridae Subfamilies: Lentivirinae Oncovirinae Spumavirinae Species: HIV-1, HIV-2 Human T-cell leukemia virus. Structure of HIV. Major antigens of HIV.

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Retroviruses. Human immunodeficiency virus. Oncogenic viruses. Mechanisms of viral oncogenesis

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  1. Retroviruses. Human immunodeficiency virus. Oncogenic viruses. Mechanisms of viral oncogenesis

  2. Classification • Family Retroviridae • Subfamilies: • Lentivirinae • Oncovirinae • Spumavirinae Species: HIV-1, HIV-2 Human T-cell leukemia virus

  3. Structure of HIV

  4. Major antigens of HIV • Envelope antigens: • gp 120 • gp 41 • Shell antigen: • p 18 • Core antigens: • p 24 (matrix protein) • p 7; p 9 • Viral enzymes – p11 (integrase); p31 (protease); p 51 (reverse transcriptase)

  5. Epidemiology • Three modes of transmission: • sexual intercourse • parenteral • perinatal

  6. Pathogenesis • Virus affects cells, carrying CD4 receptor • T- lymphocytes (helper), • B- lymphocytes, • monocytes, • macrophages, • glial cells, • microglia, • follicular dendritic cells

  7. Live cycle of the HIV into infected cell

  8. Releasing of the progeny virions from infected T-helper by budding

  9. Clinicalstages • Group 1 – Acute HIV infection. • Group 2 – Asymptomatic infection • Group 3 - Persistent generalized lymphadenopathy • Group 4 – Syptomatic HIV infections (AIDS)

  10. HIV-associated opportunistic infections • Bacterial infections: tuberculosis, shigellosis, salmonellosis, mycobacteriosis, staphylococcal and streptococcal purulent infections, etc. • Fungal infections: generalized candidosis, cryptococcal infection, histoplasmosis • Protozoan invasions: pneumocystosis, toxoplasmosis, amoebaean dysentery, lambliosis • Viral infections: generalized herpetic infection, CMV, VEB, sarcoma Kaposhi

  11. Sarcoma Kaposhi

  12. Laboratory diagnosis Specific tests for early diagnosis of HIV infections: • Antigen detections • Detection of viral nucleic acid Laboratory diagnosis during seroconversion period: Antibody detection: • Primary: ELISA test (anti gp120, anti gp41) • Confirming: Western blot test Non-specific tests (immune status assay) Tests for opportunistic infections and tumors

  13. Main markers of the HIV-infection in different stages of disease

  14. Prevention and therapy Prevention – non-specific Antiretroviral drugs include: • Nucleoside inhibitors • Non-nucleoside inhibitors of reverse transcriptase • Viral protease inhibitors • Fusion inhibitor

  15. Oncogenic Viruses • Viruses that produce tumours in their natural hosts or in experimental animals or induce malignant transformation of cell in culture, are known asoncogenic viruses.

  16. List of oncogenic viruses onc(+) • RNA viruses • Retroviruses Avian leucosis viruses Murine leucosis viruses Mammary tumour viruses of mice Leucosis-sarcoma viruses of various animals Human T-cell leukemia viruses

  17. List of oncogenic viruses • DNA viruses • Papovavirus • Papillomaviruses of human beings, rabbits and other animals • Polyomavirus • Simian virus 40 • BK and JV viruses • Poxvirus • Molluscum contagiosum virus • Yaba virus • Shope fibroma

  18. Papillomas (warts)

  19. List of oncogenic viruses (onc(-) • Adenovirus • Many human or nonhuman types • Herpes viruses • Epstein-Barr virus • Herpes simplex virus types 1 and 2 • Cytomegalovirus 5. Hepatitis B and C viruses– primary hepatocellular carcinoma

  20. Oncogenes • Viral oncogenes (V-onc). • Cellular oncogenes (C-onc) • Protooncogenes

  21. Mechanisms of viral oncogenesis of RNA-viruses • Following hypothesis are suggested: • Provirus hypothesis • Protovirus hypothesis • DNA oncogenic virus hypothesis

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