In this video, we're going to talk about some of the different types of cytokines, and we're only going to talk briefly about 5 of the different types of cytokines. Notice that each of these 5 bullet points that you see here in the text corresponds with the 5 different types of cytokines that we're going to talk about, and notice that each of these five sections of our image down below corresponds with the 5 different types of cytokines that we'll discuss up above. The first type of cytokine that we're going to talk about are called chemokines, and chemokines are cytokines that allow for a process known as chemotaxis. Chemotaxis involves the movement of a cell either towards a chemical signal or away from a chemical signal depending on the type of chemokine that is released and detected. These chemokines can be crucial for the recruitment of immune cells so that those immune cells can travel to the infection sites and help eliminate the microbes found at those infection sites. If we take a look at our image down below on the far left-hand side, notice this is an image corresponding with these chemokines. Once again, chemokines are important for chemotaxis, allowing cells to move towards or away from a chemical. These chemokines are here in purple, and can be detected by immune system cells, which then migrate or travel to the site of infection, and therefore eliminate the microbes found at the site of infection.
The second type of cytokine that we're going to talk about are called colony-stimulating factors, and as their name implies, they are important for stimulating the growth and differentiation of immature leukocytes, or immature white blood cells in the bone marrow. Depending on the types of colony-stimulating factors that are released and detected, that will dictate what types of leukocytes the stem cells will grow and differentiate into. If we take a look at our image down below at this next section, we're focusing on the colony-stimulating factors, which are represented by these little blue circles. These colony-stimulating factors can be detected by lymphoid progenitor cells or hematopoietic stem cells, and it will dictate how that cell grows and differentiates. Depending on the types of colony-stimulating factors that are produced and detected, it will dictate what types of immune system cells or leukocytes are going to be generated.
The next type of cytokine that we're going to talk about are called interferons, commonly abbreviated as IFNs. These interferons or IFNs provide antiviral effects or defense against viruses to neighboring cells that detect the interferons. Later in our course, we will talk about the interferon response in much more detail. But for now, if we take a look at this next section of our image right here, this is focusing on the interferons. These interferons are being represented by these little orange circles, and they will be produced by one cell and detected by a neighboring cell. That neighboring cell will be able to create defense against infection, defending itself from viruses, providing antiviral defenses, or microbial defenses to the neighboring cell that detects the interferons.
The next type of cytokine that we're going to introduce here is called the tumor necrosis factor or TNF for short. As its name implies, it was originally discovered for its primary role in killing tumor cells, but it also has alternative roles. For example, it initiates the inflammatory response or inflammation. It can also initiate another process known as apoptosis, which is really just a fancy word for programmed cell death. It will only initiate apoptosis in infected cells that have been infected by a virus or some other kind of microbe. Taking a look here at the next section of our image, we have the tumor necrosis factors being represented by these little gray circles. Notice that these tumor necrosis factors, upon being released, can either lead to killing of tumor cells or they can cause inflammation or apoptosis.
The last type of cytokines that we're going to talk about are the interleukins, which, notice by this underlying leuk part, is going to imply that these are cytokines that serve as communication molecules between leukocytes. You can see the leuk in leukocytes and the leuk in interleukins can help remind you of that. Notice this image on the far right-hand side over here is focused on these interleukins. The interleukins here are being represented by these little pink circles. Again, these interleukins can be released by one leukocyte and detected by another leukocyte to allow for leukocyte communication, and they have a wide variety of different effects. As we move forward in our course, we'll be able to talk about some of the different types of interleukins, and we'll be able to talk about that in another video as we move forward.
This here concludes our brief lesson on some of the different types of cytokines, and we'll be able to apply some of these concepts as we move forward in our course. I'll see you all in our next video.
