Immune System

4. Large white blood cells that consume bacteria and dead cells.
9. Proteins made by B cells to fight specific antigens.
13. Swelling and redness caused by the immune system’s response to injury or infection.
14. A substance that teaches the immune system to recognize and fight certain diseases.
16. A rise in body temperature to fight infections.
17. A condition where the immune system attacks the body’s own tissues.
18. An overreaction of the immune system to harmless substances.
19. A tiny particle that invades living cells to reproduce.
21. A sticky substance in the nose and throat that traps germs.
23. The invasion of the body by harmful microorganisms.
24. A gland where certain white blood cells mature.

1. ______ system ; The body’s defense system against infections and diseases.
2. _______ Nodes; Small glands that filter out harmful substances.
3. An organism that lives on or in a host, causing harm.
5. Cells that "eat" or destroy harmful invaders.
6. The body’s first line of defense against harmful invaders.
7. An organ that helps filter blood and fight infections.
8. A substance that triggers an immune response.
10. The body’s ability to resist infection.
11. _____ Blood Cells that fight infections; also called leukocytes.
12. Single-celled organisms, some of which can cause disease.
15. White blood cells that target specific invaders (e.g., B cells and T cells).
20. A type of organism that can infect the body, like yeast or mold.
22. A harmful microorganism like a virus or bacteria.