Immune System Collaboration

Hi in this video I'm gonna be talking about immune system collaboration. So when we get affect an infection or some type of pathogen, it's not only one part of the immune system that responds all of it responds. So now I want to kind of connect all these pieces together and figure out how are all these things activated and how are they responding? So the immune, the innate immune system is responsible for first responding to a pathogen. So how this happens is you have some kind of pattern recognition receptor. So like toll like receptors are going to recognize the pathogen that's present in the blood or on the skin or wherever it is this is going to activate. These cells usually causes these white blood cells or macrophages to take up the pathogen. They begin degrading it and they eventually presented via these MHC molecules that we talked about. So now we have this infection. These cells have taken it up and now they're presenting it on the surface. So um when they're presented that begins to activate other cells. So dendritic cells are an example of this antigen presenting cell, they're part of the innate immune system that present these antigens and activate these t helper cells. So then once t helper cells are activated they begin to secrete inflammatory molecules. These are called cytokines, cytokines do have a lot of functions. There's a ton of them that are going to talk about all of them. But essentially they're inflammatory molecules. So what do they do? They promote inflation. So they increase the numbers of white blood cells around. They help the white blood cells migrate to the infection site and they increase cell adhesion molecules. So these white blood cells can attach to all the blood vessels and travel to the area where infection is and keep stay there until the infection resolves. So now we talked about the dendritic cells are part of the innate immune system but the t cells are part of the adaptive immune system. So now those T helper cells are activated so they further and activate the innate which is what this is. But they also inactivate other cells that are part of the adaptive. So these um T. Helper cells there's kind of two classes of them. So the th one cells are gonna go on to macrophages which I talked about and the site of toxic T cells which go on to kill the internalized pathogens. Then you have the th two cells which come in and activate B cells to secrete antibodies to target extra cellular pathogens. So sort of innate immune system activates the T. Helper cells. And those t helper cells go on to further activate the immune system but also activate site a toxic T cells B cells all these other cells that are important in the adaptive immune system. So here we have this same exact picture again but we're going to talk about it from a different way. So here we have an A. P. C. This could be like a dendritic cell takes up the ante jen chops it up, presents it via the MHC molecules to probably a T. Helper cell T helper cell then goes on and can release cytokines that go on to activate Cida toxics details where are the side a toxic T. Cells? They can activate B cells to produce antibodies. They can activate more helper T cells which release these side of kinds here that help activating macrophages or other types of white blood cells that are super important. So this is a great example not only a T cell development and the different T cell types but how the process of connecting the innate immune system to the adaptive immune system works when we are infected with something. So hopefully that's clear. So with that let's now move on.

Choose the following with the proper order of immune system activation.

• A. B cell → T cell → Dendritic cell → infection
• B. Infection → T cell → Dendritic cell → B cell
• C. Infection → dendritic cell → T cell → B cell
• D. Infection → B cell → dendritic cell → T cell