Good morning! Today we're going to do a deep "dive" (get ready for more fish puns!) into respiratory immunology and why it's so important to study. Got any Q's? Send them my way!
@madina_wane
@madina_wane
Let's start with some immunology basics! The immune system is a complex system of cells which patrol the body to fight off infections & cancer, and repair damaged tissue. There a loads of different immune cells but here are three to get us started 
Image description: Drawing of three different immune cells and their functions described. 1. B cells make antibodies to trap pathogens. 2. T cells can kill infected cells to stop infections from spreading. 3. Macrophages can 'eat' debris, dead cells, and pathogens.
@madina_wane
@madina_wane
Immune cells are all over the body! But let's focus on mucosal tissues - these are tissues that are exposed to the external environment and covered by a protective mucus layer. Slimy but very important 😂 These tissues include lungs and the gut amongst others @madina_wane
Let's take the nose as an example.
It's lined with a layer of cells, known as epithelial cells, covered by sticky mucus. This can trap pathogens and prevent infection, but sometimes pathogens like viruses can still get through - viruses like influenza!
@madina_wane
It's lined with a layer of cells, known as epithelial cells, covered by sticky mucus. This can trap pathogens and prevent infection, but sometimes pathogens like viruses can still get through - viruses like influenza!
@madina_wane
Once a cell is infected by a virus, it can send out signals which attracts immune cells to get rid of the infection (like T cells and macrophages)...this doesn't always work perfectly and means that some people get sick.
@madina_wane
@madina_wane
So what viruses are we talking about? There's a bunch! Including influenza, rhinoviruses (cause colds), SARS, and of course SARS-CoV2 which causes COVID. Unfortunately we only have vaccines for influenza, and even that one we have to change every year 😵
@madina_wane
@madina_wane
So to develop effective treatments and vaccines against these viruses we need to understand how the immune system reacts. Specifically how it reacts in the nose/lungs at the site of infection.
Although we think of the immune system as protective, it can also be damaging. It can overreact and send too many immune cells to the lungs. These produce compounds that damage the tissue. This is a 'cytokine storm' and is the reason you feel sick with the flu! @madina_wane
There is evidence that cytokine storms also happen during COVID-19, especially in severe disease. But exactly how this happens and the immune cells involved in this phenomenon are still being investigated 🤔
@madina_wane
@madina_wane
But recently, a drug normally used to dampen inflammation from the immune system (dexamethasone), seems to be helping severely ill COVID patients. So it does seem like this "overreaction" can be countered!
@madina_wane
@madina_wane
Sometimes the immune system doesn't overreact, but responds in the wrong way. Different types of responses are needed to fight different pathogens, for examples parasitic worms or bacteria. If this goes wrong this can cause damage and make the infection worse!
@madina_wane
@madina_wane
Scientists have to consider this when developing vaccines. How do you make sure the body responds in the "correct" way that will leave the patient protected and not cause damage? That's why we have to understand the basics of the immune response!
@madina_wane
@madina_wane
That's it for today's thread on respiratory #immunology! Feel free to ask any questions though!
I'll be back tomorrow talking about my path into research
@madina_wane
I'll be back tomorrow talking about my path into research
@madina_wane
