The Immune System

Step One: Pathogens (all the same type) enter the body and they all have the same antigens on theie surface.

Step Two: Pathogens in the blood come into contact with lymphocytes. Different lymphocytes have differently shaped antibodies on their surface.

Step Three: Lymphocytes that have antibodies that match the antigens to the pthogen and become activated.

Step Four: Activated Lymphocytes divide rapidly to produce many identical copies (clones) with the same antibodies on their surface.

Step Five: Some of the lymphocytes release lots of antbodies into the blood.

Step Six: The antobodies attatch to the pathogens and cause them to die.

Step Seven: When all the pathogens are dead, a few memory lymphocytes remain in the blood.