In this video, we're going to talk more generally about the functions of helper T cells, or TH cells, and we're going to focus specifically on the activation of macrophages. Now first, we need to recall from some of our previous lesson videos that naive helper T cells, or inactive helper T cells, can become activated by dendritic cells that are antigen-presenting and presenting antigens on their MHC class 2 molecules. Now, unlike the cytotoxic T cells whose function is to mainly induce apoptosis in infected cells, helper T cells don't induce apoptosis in other cells. Instead, helper T cells or TH cells, they are going to make cytokines or communication signals that ultimately help to stimulate and activate other immune cells, improving the immune capabilities of immune cells around it. And so it can improve or activate the immune cells such as macrophages, naive cytotoxic T cells, and B cells as well.
Now here in this video, we're going to specifically focus on the ability for helper T cells to activate macrophages. And so macrophages, they are routinely engulfing, degrading, and processing invading pathogens in many of our different tissues. And this is something that they do on a routine basis. And what they can do is they can also present these pathogens as antigens on their MHC class 2 molecules. Now effector helper T cells are capable of binding to the antigens presented on MHC class 2, and that will activate the helper T cells. And the activated helper T cells, again, will produce cytokines that are capable of activating other immune cells or stimulating the macrophages even further, improving their immune capabilities.
And so these stimulated or activated macrophages have increased production of lysozymes, which we'll call organelles involved with destruction, degrading, and also increased production of antimicrobials that can destroy invaders more effectively. And so the helper T cell helps the macrophage destroy invaders more effectively. Now the helper T cells can also release additional cytokines to get rid of invaders even better. And so if we take a look at our image down below, we can get a better understanding of the functions of these helper T cells. Now notice on the left over here what we're showing you is a macrophage. And so really the top half of this image here is just a cartoon version of another they're showing the same thing just in a different way. And so what we have is a macrophage, and the macrophage is not yet activated. And so these macrophages, they are commonly and routinely engulfing, degrading, and processing pathogens. So they have an invading pathogen here and the macrophage will engulf it, degrade it, break it down, and then present it on its surface, at on these MHC class 2 molecules. And so you can see here our macrophage is presenting the antigens on its MHC class 2 molecules.
And so, what you'll notice is that when a helper T cell recognizes the antigen on an MHC class 2 molecule, the helper T cell can release cytokines. And these cytokines here can have an impact on the macrophage, and it can activate the macrophage. And so notice here we have our helper T cell is somewhat presenting these cytokines to the macrophage, and the macrophage is taking it in. And that improves the destructive capabilities of the macrophage so that we have an activated or stimulated macrophage. And so now it's capable of killing the invaders even more effectively. And so down below what we're showing you is again the activated or the stimulated macrophage with improved, destructive immune abilities. And so really that's what these helper T cells do; they help other immune cells improve their destructive immune abilities even further.
And so this concludes our brief lesson on the general functions of helper T cells and their ability to activate macrophages. And we'll be able to get some practice applying these concepts as we move forward in our course. So, I'll see you all in our next video.