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Asked by anon-251613 on 1 May 2020.
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Delma Childers answered on 1 May 2020:
I would divide white blood cells into two major classes, at least from an infection point-of-view. First, there are the innate immune cells. These include macrophages, neutrophils, and other cells that circulate around the body and provide a basic first line of defense against infections. They have lots of other functions and some of these cells are involved in allergies, but this is the first major category I think about for fungal/bacterial/viral infections. The second class involves lymphocytes, which are part of the adaptive immune system. This class includes T cells and B cells and they can take a few days to get activated because they will use very specific, unique tools to fight each infection. T cells can help coordinate innate immune cell activities for destroying infectious cells. B cells produce antibodies that help tag infectious agents for other immune cells to destroy.
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Keith Boyle answered on 1 May 2020:
To briefly add to Delma’s excellent answer and because a certain type of white blood cell is quite close to my heart (not literally!), the neutrophil. This cell type, together with macrophages and dendritic cells, actively survey our bodies for invading pathogens. They have the remarkable ability to physically eat those pathogens by a process called phagocytosis. Neutrophils are incredibly efficient at this and have evolved to have a very odd-shaped nuclues that allows them to squeeze through tiny gaps between our cells to find those pathogens. Macrophages and dendritic cells take information from the pathogens and instruct how T cells and B cells should then respond. Some pathogens are much to big to eat phagocytosed, for example a parasitic worm. These are attacked by neutrophils, which basically spill their contents onto the worm to try destroy it.
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Linnea Drexhage answered on 1 May 2020:
Hiya! Just to add on to these two excellent answers in a more broad way: there are two types.The ones that react very quickly but are less specialised (innate immune system). And if they can’t solve the problem there is a second type, the adaptive immune system. These cells are able to respond super specifically to exactly what kind of germ is attacking the body. The adaptive system is a bit slower but is highly specific and usually does a great job at clearing the infection. Once the adaptive response has happened, antibodies can be detected in the blood and memory cells, which are also white blood cells, are formed. They can live for a very long time and make sure that if the body ever gets in contact with the same germ again, the response will be super fast. Let us know if you have more questions or need us to explain something again!
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Ailith Ewing answered on 2 May 2020:
Just to add a different perspective to these already great answers, different cell types including different types of white blood cell vary in terms of which genes are turned on and off. This means that we can look at each type of cell in the lab and find a different combination of which genes are turned on and off for each type of cell. These are usually called signatures of gene expression and are really useful!
If we have a sample taken from a patient usually that’s made up of lots of different types of cell. To find out how many cells there are of each type in the sample we can measure how genes are turned on and off on average across the whole sample and then use mathematical techniques to work out what the best combination of the cell type specific gene expression signatures (that we found in the lab) is so that it is closest to the average pattern seen across all the cells. This combination then lets us estimate how much of each type of cell there is in the sample.
This is a really useful way of working out if there are a lot of immune cells in general in a sample taken from a patient and also what type they are!
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Bilal Ahsan answered on 2 May 2020:
All the answers are great and there is hardly something left. I would like to answer from another perspective. White blood cells can be
1. Granulocytes: have tiny granules in the cytoplasm and contain segmented nuclei, hence also called polymorphonuclear leukocytes. Examples are neutrophils, eosinophils, and basophils.
2. Agranulocytes; do not have cytoplasmic granules and their nucleus is nonsegmented, hence they are also known as mononuclear leukocytes. Examples are Monocytes and Lymphocytes.
Function of each type of White Blood Cells is already elaborated by Delma, Keith and Linnea. -
Nina Rzechorzek answered on 2 May 2020:
Hi abiiii, great answers already. Here are some nice overviews with pictures and a video clip:
https://www.histology.leeds.ac.uk/blood/blood_wbc.php
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Emma Lloyd answered on 3 May 2020: last edited 2 May 2020 11:06 pm
There are so many different types of white blood cells! Generally they’re separated into two major classes, those of the innate immune system and those of the adaptive immune system. Innate immune cells include macrophages and neutrophils that circulate in the blood and act as the first line of defence against pathogens, they are less specialised than those of the adaptive immune system. The cells in the adaptive immune system are responsible for producing an antibody response against a pathogen, the most commonly known are T cells and B cells.
Also, white blood cells vary widely in shape and when you look at different innate immune cells under the microscope, you can easily tell the difference between types by looking at the shape of the nucleus.
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James Loan answered on 5 May 2020:
A lot has been covered already! Just one thought to add: white blood cells (and many other cells in the body) vary with age. Both as an individual cell ages and also as the person to whom it belongs. This can have important effects; changes in how white blood cells and other immune cells found in each organ respond to substances such as pollen are related to how many people can have allergies or asthma at a young age and then grow out of them.
Conversely, changes in how these cells function in older adults might explain partly how certain diseases are more likely in older age – for example the changes to blood vessels that cause heart attacks and stroke may be accelerated because of how white blood cells change with age.
Understanding what is the purpose of these age-related changes is as important as understanding how we can artificially manipulate them.
Comments
Lucy commented on :
To add to Delma’s great answer, the same type of white blood cell also vary a lot from person to person. They vary between people a lot more than other cell types in the body. This is because it’s really important to have a variety of immune responses in a population. If every person had identical immune systems then one nasty disease could wipe out the whole population. Therefore there’s a really big evolutionary pressure to have variety in the immune system. The adaptive immune system, which Delma described, shows the most variation between people. The cells of the immune system can literally reshuffle their genes to make an infinite number of combinations of receptors on their surface. These different receptors are what allows the adaptive immune system to make a specialised cell, like a T cell, to fight a specific disease. Once the disease has been cleared from the body, a small number of these cells turn themselves into “memory cells”; this is what gives you “immunity” and protects you from reinfection from the same disease twice. Because the process of “gene reshuffling” is random, it takes a while for your body to produce an effective adaptive immune response. The innate immune response fights the disease in the meantime. This random reshuffling is also why some people are more immune to diseases than others – it can just be that their bodies made a better set of adaptive immune cells for that particular disease!