Immune Module - The Perfect Fit

How B and T Cells Distinguish Among Germs And Your Own Cells

Pre-Lab Information

What different mechanisms are used to fight off germs when they come into contact with your body? Simple! The answer is white blood cells. These cells are made to fight off any foreign germ or any infected cell. Although while these cells help fight off these things, how can they tell them apart from your typical body cells?

Different types of cells have different shapes. Those shapes are there for the B and T cells (white blood cells also called lymphocytes) to distinguish between your own body cells and germs entering your body. Both B and T cells have special receptors that target a special antigen. When an unknown cell comes around B and T cells, they identify if they're a germ by seeing if the shape fits into it's receptor. If the shape fits, it means it's a germ or infected cell and the white blood cell eliminates it.

Specifics of B and T Cells

B and T cells can only recognize one kind of germ or infected cell, causing your body to create many different types of receptors. Your body has to make billions of receptors in order to match any type of germ. Typically, when a white blood cell comes into contact with a harmful substance it will create an effective match (eliminating the intruder).

B cells infect foreign molecules with a dissolvable protein in order to eliminate them

T cells help make other lymphocytes needed and they also detect and kill host cells


Your group will be given a white blood cell (piece of clay) with a certain shape molded in it, showing it's receptor shape. You'll then have to find a group with the matching antigen. If your antigen does not match with a receptor, don't worry! It's just a typical body cell that does not need to be destroyed. Once you find your match, say "Perfect fit!"

Additional Information

Once a T or B cell's receptor notices there's an antigen, they begin making millions of copies of that certain white blood cell to fight it. That cell then fights the antigen until it is gone. Your body then keeps more of that type of white blood cell just in case that same thing were to come back. It could then fight it quicker and more efficiently.
Created by: Sarah Thomas, Trevor Cox, Jenny Anderson, and Bryan Sivelle