Today I taught monoclonal antibodies to Year 11; the first time I’ve taught this since the mass release of lateral flow tests, so it was so exciting to have an incredibly relevant example to work with. I thought I’d share how I approach it (AQA specification).
I find it’s important to start off by explaining that monoclonal antibodies are not a “natural” thing. Biologists have learnt about how the immune system works and have utilised the cells and proteins in the system to develop a new technology. This is important as I’ve had some students early on misunderstand and think this all happens naturally in an organism. I explain that biologists know antibodies are a very specific shape and will bind to one specific shaped antigen (all by Q&A to see what they recall from last lesson). I describe antibodies as Y-shaped proteins with two “grabby hands” (antigen binding sites) – each one can “grab” (bind to) one antigen. The “hands” are all slightly different shapes depending on which antigen they bind to. I have a toy antibody from Giant Microbes which is a useful prop, but you could cut out a Y-shaped piece of card.
My next step is to show them the great video on the BBC Bitesize website (blank diagram and question sheet in the resources section below. We review the theory of how monoclonal antibodies are made by annotating the diagram below and checking our answers to the questions that accompany the video.
Then we discuss what monoclonal antibodies can be used for. It seemed daft not to discuss lateral flow tests as most of the students have been using them regularly! I showed them Prof. Mark Lorch’s fantastic LFT dissection video on YouTube to start with (@Mark_Lorch on Twitter). For a bit of added drama, one of the students volunteered to take an LFT live in the lesson – I chose someone who had taken a negative test this morning to avoid the nightmare situation of it turning positive in front of my eyes. This led to an interesting side discussion about false positives and false negatives.
After that we checked what we understood from the video by acting out how a monoclonal antibody test kit worked. I used to people on my front row to be the “Test” line and the “Control” line (see image below). I used the soft-toy antibody and it’s removable antigen to assist me. I held the antigen and told the class I was in the “Sample” section of the test kit. I then took a few steps along to the section where the antibodies were. The antigen and the antibody joined. I took another few steps along to Ben who was an antibody in the “Test” window; he could grab any antigens that moved past him. I explained in reality there would be many antibodies so some of them wouldn’t bind. I took a few steps on to Zak who was an antibody in the “Control” window. He could grab any unbound antibodies. We repeated the demo without the presence of an antigen and they could see how only the control line would change colour.
We then discussed other uses of monoclonal antibodies, including a bit of revision of the plant disease topic we did in Year 10. There are some more examples on the PowerPoint in the resources section below, but another important one I tell them about is rapid testing for HIV, and how revolutionary that was; it led to a good discussion about the advantages of a monoclonal antibody test over a blood test. The notes I gave the students are straight from the specification and are shown on the image below.
Finally, we had around 25 minutes left of the lesson so I had them complete some past paper questions (see resources section below) about monoclonal antibodies. HUGE thank you to @Alex_Crone who saved me time this weekend finding new-spec past paper questions for them to have a go at.
Resources:
Pedagoggles 