https://www.khanacademy.org/science/ka-biology-grade-12/x406cf103e0507862:in-in-human-health-and-disease/x406cf103e0507862:in-in-types-of-immunity-and-the-immune-system/e/allergies 2026-04-08T00:54:09.631945657Z Allergies Symptoms, causes and treatment of allergic reactions exercise https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/introduction-to-immunology/v/self-versus-non-self 2023-12-04T19:02:25.924542584Z Self vs. non-self immunity The immune system's main job is to fight off harmful invaders like bacteria and viruses. This is achieved through a two-step process. First, B cells and T cells that react to our own proteins are eliminated during their development. Second, even if some of these cells escape, they need a matching T cell to activate them. This system isn't perfect, and when it fails, it can lead to autoimmune diseases. Patrick van Nieuwenhuizen video https://cdn.kastatic.org/googleusercontent/vE7HtOgPInCroD7UAzjGu1kpXL4VkSpfp_yBspyQHC9y4uZgMawiTo5rF-RNGy-qm4N4RdBY6ShpwhxNP-lBW20 Self vs. non-self immunity The immune system's main job is to fight off harmful invaders like bacteria and viruses. This is achieved through a two-step process. First, B cells and T cells that react to our own proteins are eliminated during their development. Second, even if some of these cells escape, they need a matching T cell to activate them. This system isn't perfect, and when it fails, it can lead to autoimmune diseases. https://cdn.kastatic.org/ka-youtube-converted/afM6_VFaIss.mp4/afM6_VFaIss.mp4 869 Immune disorders https://www.khanacademy.org/science/als-k-to-12-science/x46c2fc9f8e023990:2nd-quarter/x46c2fc9f8e023990:the-muscular-system-structure-function-and-movement/e/muscular-system---passage-1 2024-12-03T20:25:06.58002304Z Mini MCAT passage: Autoimmune disorders of the muscle Gilbert Lerma exercise