T1 L22: Immunology of COVID-19

Question 1

What are the characteristics of SARS-CoV-2 and related viruses?

Answer 1

It’s a positive-sense, single stranded RNA virus that infects vertebrates and invertebrates

Replication of virus occurs in the cytoplasm

Question 2

How does SARS-CoV-2 enter a cell?

Answer 2

ACE2 receptor

TMPRSS2, CD147, and FURIN are enzymes that facilitate entry

Question 3

Where are ACE2 receptors expressed in the body?

Answer 3

Lungs mostly

Question 4

What are the target organs of SARS-CoV-2 and what are the symptoms?

Answer 4

• Lung: pneumonia
• Vasculature: vasculitis contributing to thrombotic events
• Gut: diarrhoea, pain, loss of appetite
• CNS: vasculitis causing confusion
• Muscle: fatigue/weakness, myalgia
• Naso and oropharynx: affacts the sensory neuroepithelium causing loss of smell and taste

Question 5

Why do horseshoe bats not get ill from SARS-CoV-2?

Answer 5

• They have a naturally high body temperature

- They also have a STING mutation that makes the infection less potent

Question 6

Why is spike glycoprotein the most immunogenic on SARS-CoV-2?

Answer 6

Because it’s by far the longest so has the greatest chance of producing peptides that can be recognised by the immune system

Question 7

What is trained immunity?

Answer 7

The ability of the innate immune system to form immune memory and provide long-lasting protection against foreign invaders

Can be a result of recent vaccine or infection

Question 8

What are some maladaptive states of innate immunity?

Answer 8

Immune response failure
Hyperinflammation
Atherosclerosis

Question 9

What is ‘long COVID’?

Answer 9

Persistent symptoms beyond 12 weeks from acute disease