84. COVID19 inside the body 3: immune response, antibodies, T-Cells, B-Cells and macrophages

In this series, Timothy Trudgen and Biritjalawuy Goṉḏarra explain how the COVID-19 virus travels through the mouth into the throat and, when it enters the lungs, it can cause significant infection there. White blood cells detect and fight germs to stop diseases forming in the body. To do this, white blood cells have specific roles to detect and test invading cells to recognise if the cells are different from the body’s own cells. White blood cells sense the nature of the germ cell and communicate this to other white blood cells to continue the immune system defence process.

In Story No.2, Timothy and Biritjalawuy describe how the specialised roles of white blood cells called macrophages, T-cells and B-cells, work together to protect the body.  When macrophages detect an invading germ, they eat the germ and release a substance called cytokines to attract other white blood cells.  B-cells have weapons like spears called antibodies. Macrophages do not destroy body cells but T-cells do. They are the leaders of the immune system defence process.  T-cells that are able to destroy body cells that have virus inside them are called killer T-cells.

In Story No.3, they explain how the immune system detects viruses like COVID-19 in the throat.  When a white blood cell detects a virus cell, it attracts other more specialised cells with cytokines to further test the virus cell. When T-cells detect a virus, they communicate about this with macrophages. T-cells test the invading cells further and send a message to attract B-cells to come and make antibodies. The immune system response is a pathway, a chain of responses by specialised cells.

Another example is when cells are damaged, e.g. if you have a cut on your hand, the damaged cells send a chemical message called cytokines that attracts attention to the area, stimulating a movement of cells there. This makes inflammation by increasing water, white blood cells and heat in the area, to stop invading cells from reproducing. The extra water in the blood moves from the capillaries and into the wound.

In Story No.4, the pair discuss how white blood cells protect the body from virus cells like COVID-19.  Capillaries are very small blood vessels with slight gaps between the cells that form the vessel walls. Larger vessels do not have gaps between the cells of the vessel walls so no blood moves out through the vessel wall, but capillary walls have gaps that allow white blood cells and antibodies to pass through.

An immune response to COVID-19 is a sore throat and raised temperature as the body is activated to fight invading cells. This is where the expression, “the body is fighting this sickness,” comes from.

In Story No.5, Timothy and Biritjalawuy explain that when T-cells recognise an invading cell, they communicate to B-cells instructing them to produce a specific antibody. The antibody is like a kind of spear with specific spear heads, in the same way that different spears are used for hunting wallaby, turtles, fish and dugong.  B-cells ‘spear’ invading cells at a surface level only, so the cell is wounded enough to prevent reproduction. It is not killed by the antibodies. The killer T-cells are attracted to come to the site to kill body cells that are marked with an attached antibody because they have viruses inside them.

In Story No.6, Tim and Biritjalawuy describe how once a body cell with a virus inside it is marked with an antibody, a killer T cell destroys it quickly.  Viruses damage the area they are in within the body and different viruses have different disease processes. Viruses in the throat can do some damage, but viruses in the lungs can cause significant damage to the fragile lung membranes, affecting how air transfers to blood.

 

There are 6 Stories in this podcast. Please see time stamps below –

  • Story No. 1 COVID19 inside the body: Immune response Part 1                             00:00
  • Story No. 2 COVID19 inside the body: Immune response Part 2                             10:10
  • Story No. 3 COVID19 inside the body: Immune response Part 3                             17:44
  • Story No. 4 COVID19 inside the body: Immune response Part 4                             28:34
  • Story No. 5 COVID19 inside the body: Antibodies, T-Cells, B-Cells and Macrophage Part 1  39:46
  • Story No. 6 COVID19 inside the body: Antibodies, T-Cells, B-Cells and Macrophage Part 2  48:30