a foreign substance that invades your body is called an <u>A</u><u>N</u><u>T</u><u>I</u><u>G</u><u>E</u><u>N</u>. 8. When your body detects an antigen, antibodies are made and lock onto it. Once an antigen is recognized, your immune system can remember it the next time and protect you from getting sick again.
