MSE 2020 L16

Applied Cell Biology Part 2 - HIV

What is HIV?

• Retrovirus that infects and replicated in human immune cells, particularly CD4+ T Cells

• It can lead to progressive depletion of immune cells, making the immune system more weak

How is HIV transmitted?

The exchange of bodily fluids e.g. blood, semen, vaginal secretions, breast milk

What symptoms are associated with HIV infection?

1. Acute phase of flu-like symptoms

2. Period of clinical latency

3. Eventual development into AIDS

How can we manage HIV?

• Antiretroviral therapy (ART) - using combination drugs to target different steps within viral life cycle

• People living with HIV can achieve long-term survival and improved QOLF

What are CD4+ T Cells?

• Lymphocytes

• Produce various cytokines e.g. interferons, TNF and IL-2, 4, 10 and 14

What is the structure of CD4+ T cells?

• Four extracellular immunoglobulin domains (D1 to D4)

• Transmembrane domain

• Cytoplasmic tail

What does the D1 domain at the N-terminus do?

Binds MHC class II molecules to antigen-presenting molecules

What do the cytoplasmic tails do?

Interacts with Lck kinase, which initiates T-cell receptor signalling upon antigen recpetion

Where did HIC come from?

• 1980s: First cases among gay men with unusual infections and cancers

• Originated from a related virus in non-human through zoonotic transmission to humans in central Africa

• Earliest case is from the Congo in 1959

What are retroviruses?

Enveloped RNA viruses that replicated in a host cell through reverse transcription

What are some examples of retroviruses?

• HIV

• HTLV-1 (linked to adult T-cell leukaemia)

• several animal diseases

How can retroviruses promote cancer?

1. Carrying oncogenes for tumour grown

2. Inserting their DNA into host cell genome, activating cellular oncogenes

Why are retroviruses important in medicine?

THey can be used as vectors to deliver corrective genes into cells because they can intergrate genetic material

How is HIV structured?

• Single stranded Positive DNA genome w 9.000 nucleotides and is a diploid

• Organised with overlapping reading frames and splicing events that allow for multiple different proteins form same RNA sequence

What are examples of HIV genes?