Antigens and autoimmune diseases (CIE A-level Biology)

This lesson describes self and non-self antigens and how a failure to distinguish between the two is the mechanism of autoimmune diseases. The PowerPoint and accompanying worksheets have been primarily designed to cover points 11.1 (d & f) of the CIE A-level Biology specification and describe examples of these diseases including myasthenia gravis, but this lesson can also be used to revise the content of the earlier topics as well as the previous lessons in topic 10 & 11 through the range of activities that are included

The first part of the lesson focuses on the antigens and explains how the failure of the immune system cells to recognise these molecules on the outside of a cell or organism elicits an immune response. Moving forwards, the students are challenged to recognise diseases from descriptions and then to use the first letters of their names to form the term, autoimmune. In doing so, the students will discover that rheumatoid arthritis, ulcerative colitis, type I diabetes mellitus, multiple sclerosis and myasthenia gravis are all examples of autoimmune diseases. The next part of the lesson focuses on the mechanism of these diseases where the immune system cells do not recognise the antigens (self-antigens) on the outside of the healthy cells, and therefore treats them as foreign antigens, resulting in the production of autoantibodies against proteins on these healthy cells and tissues. Key details of the autoimmune diseases stated above and lupus are described and links to previously covered topics as well as to future topics such as the pancreas and nervous system are made. The students will be challenged by the numerous exam-style questions, all of which have mark schemes embedded into the PowerPoint to allow for immediate assessment of progress.