Oncogenic Virus Question And Answers

Oncogenic Virus

 

Question 1. Write in brief on the oncogene virus.
Answer:

Oncogene viruses are also known as oncogenic viruses. These viruses produce tumors in their natural hosts or experimental animals or induce malignant transformation of cells in culture.

Following are the Oncogenic Viruses:

1. DNA viruses:

•  Papova virus:
  • Human papilloma virus
  • Polyoma virus
  • Simian virus 40
  • BK and JC viruses.
• Herpes viruses:
  • Herpes simplex viruses Type 1 and 2
  • Cytomegalovirus
  • Epstein-Barr virus
  • Marek’s disease virus
  • Herpesvirus saimiri.
• Hepatitis B virus.
• Pox virus.
  • Molluscum contagiosum
  • Shope fibroma virus
  • Yaba virus.
• Adenovirus

Read And Learn More: Microbiology Question And Answers

2. RNA viruses:

• Acute transforming viruses
  • Rous sarcoma virus
  • Murine leukemia-sarcoma virus.
• Slow transforming virus.
  • Mouse mammary tumor virus.
• Human T cell lymphotrophic viruses.
  • HTLV-I
  • HTLV-II.
• Hepatitis C virus.

DNA Oncogenic Virus

• Oncogenic Viruses:
  • DNA Oncogenic viruses have direct access to the host cell nucleus and are incorporated into the genome of the host cell DNA.
• Papova Virus (Human Papilloma Virus): These viruses appear to replicate in the layers of stratified squamous epithelium. It is responsible for:
  • Skin warts (Squamous cell papillomas)
  • Invasive cervical cancer
  • Condyloma acuminate
  • Other squamous cell carcinomas.
• Herpes Viruses:
  • Epstein-Barr virus: EBV infects human B lymphocytes and stimulates them to proliferate and causing Burkitts
    lymphoma, Hodgkin’s lymphoma, primary lymphoma in AIDS patients.
  • Human herpes virus 8 (HHV8): It is responsible for Kaposi’s sarcoma, a vascular neoplasm common in patients with AIDS, and also responsible for B cell lymphoma.
• Adenovirus: The human adenovirus causes upper respiratory tract infection and pharyngitis.
• Pox Viruses: In humans, they cause molluscum contagiosum and may include squamous cell papilloma.
• Hepadnaviruses: Hepatitis B virus comes into this category. It causes acute hepatitis and chronic hepatitis.

RNA Oncogenic Virus

• Acute Transforming Viruses: These consist of retroviruses which transform all cells infected by them into malignant cells rapidly. All viruses in this group possess one or more viral oncogenes. Not detected in humans.
• Slow Transforming Viruses: These oncogenic viruses cause the development of leukemias and lymphomas in different species of animals.

Human T Cell Lymphotropic Viruses

• It is the only retrovirus implicated in human cancer.
• Four types of HTLVs are recognized, i.e. HTLV-I, HTLV-II, HTLV-III, HTLV-IV
• HTLV-I leads to the adult T-cell leukemia-lymphoma
• HTLV-II leads to a T-cell variant of hairy cell leukemia.

Hepatitis C virus: Hepatitis C virus leads to hepatocellular carcinoma.