Cells and the immune system

• What makes up the HIV retrovirus?

  • Viral envelope
  • Reverse transcriptase
  • Capsid
  • RNA
  • attachment proteins (glycoproteins)
  • Matrix proteins
• HIV replication:

  • Glycoproteins on the virus surface bind to the receptors on the helper T-cells. This allows the envelope to fuse with the helper T-cells.
  • Capsid is released into the cell where it releases RNA and reverse transcriptase
  • Reverse transcriptase is used to produce DNA from the RNA template
  • The DNA is used to make HIV RNA and proteins at the host ribosomes
  • Virus particles are assembled to form new viruses which bus off from the cell membrane and go on to infect other cells
• Ways to catch HIV:

  • Having unprotected sex with an infected person
  • Close contact with an infected person‘s blood
  • Use of infected blood in a blood transfusion
  • Mother to child —> placenta or breast milk
• Treatment of AIDS:

  • Anti-retroviral drugs can reduce the viral load in the body to an undetectable level (patients cannot pass on HIV)
  • Cannot remove the virus from the body as there is not cure once HIV is acquired
  • Prevents replication by blocking the reverse transcriptase enzyme
• Prevention treatment (HIV and AIDS):

  • pre-exposure prophylaxis (prEp)
  • Is where HIV-negative individuals take anti-retrovirals before coming into contact with HIV to reduce their risk of becoming infected
• How long does it take for HIV to develop into AIDS?


  Can take up to 10 years because viruses can lay dormant as DNA within the cells