Lesson Plan

• Describe the definition of an antigen and give two common examples.
• Explain the distinction between self‑antigens and non‑self antigens, including how tolerance is maintained.
• Analyse how the immune system responds differently to self‑ and non‑self antigens.
• Apply knowledge of antigen classification to predict clinical outcomes such as autoimmunity or vaccine effectiveness.

• Projector and screen
• PowerPoint slides with antigen diagrams
• Printed worksheet with comparison table
• Sticky notes for quick‑write responses
• Model of a cell showing surface proteins (optional)

Begin with a short video clip of a virus attacking a cell to capture interest. Ask students what they think the immune system “sees” on the virus. Review prior knowledge of proteins and cell surfaces, then state that today they will identify the molecules that trigger immune responses and differentiate between self and non‑self.

1. Do‑Now (5'): Students write a quick definition of “antigen” on sticky notes; teacher collects for a brief check.
2. Direct Instruction (10'): PowerPoint explains antigen definition, examples, and the concept of immune tolerance.
3. Guided Practice (12'): Whole‑class analysis of the provided comparison table; students annotate differences between self and non‑self antigens.
4. Interactive Activity (15'): In pairs, learners complete a worksheet where they classify given substances as self or non‑self and justify their choices.
5. Formative Check (5'): Quick “exit quiz” using Kahoot or show of hands on key points.
6. Wrap‑Up (3'): Teacher summarises key take‑aways and links to upcoming topic on immune responses.

Recap the definition of antigens and the crucial difference between self and non‑self, emphasizing how tolerance prevents autoimmunity. Students complete an exit ticket stating one real‑world example of each antigen type. Assign homework: read the next textbook section on B‑cell activation and prepare a short paragraph on how antibodies target non‑self antigens.