HIV

• Describe how HIV enters Th cells

  • GP120 glycoprotein on surface of HIV
  • Binds to CD4 receptors on Th cells
  • Viral envelope fuses with cell surface membrane of Th cells
  • Viral RNA enters Th cells
• Why does destruction of Th cells, cause symptoms of AIDs?

  • Lack of Th cells reduces production of cytokines
  • Decreased activation of B cells into B plasma cells
  • Decreased production of antibodies
  • Increases risk of opportunistic infections e.g. TB
• How does HIV infect Th cells?

  • GP120 glycoprotein on HIV cell binds to CD4 receptor on THC
  • Viral envelope fuses with THC cell surface membrane
  • Viral RNA + protein enter THC
  • Reverse transcriptase in cytoplasm
  • Synthesis complementary viral RNA strand
  • To make it doubled stranded
  • Integrase inserts doubled stranded viral DNA
  • Into host cell DNA
  • Host cell's enzymes + ribosomes
  • Used to make viral proteins
  • Translated into HIV virus
  • Buds out of Th cell
  • Taking cell membrane with them
  • To form viral envelope
  • Host cell dies
  • By cell lysis