How Does Your Immune System Fight Germs?

What You'll Learn

• The immune system is your body's defense army — it fights germs that make you sick
• White blood cells are the soldiers that find and destroy germs
• Antibodies are like wanted posters — they help your body recognize germs it has seen before
• Vaccines teach your immune system to fight germs before you get sick
• Washing hands helps your immune system by keeping germs out in the first place

Words to Know

Immune system

Your body's defense army that fights germs

"My immune system fights off colds."

White blood cells

The soldier cells that hunt and destroy germs

"White blood cells rushed to fight the germ."

Antibodies

Tiny Y-shaped proteins that tag germs so your body remembers them

"Antibodies help your body recognize germs it has seen before."

Vaccine

A safe practice shot that teaches your body to fight a germ

"The vaccine trained my immune system."

Check What You Learned

Fun Facts

• The immune system is a complex network of cells, tissues, and organs that defends the body against germs

  Source: National Institute of Allergy and Infectious Diseases

• White blood cells (leukocytes) are the primary cells of the immune system that find and destroy invading germs

  Source: NIAID

• The human body produces approximately 100 billion new white blood cells every day

  Source: American Society of Hematology

• Antibodies are Y-shaped proteins produced by B cells that recognize and bind to specific germs, marking them for destruction

  Source: NIAID

• The immune system has memory — after fighting a germ once, it remembers it and can respond faster if the same germ returns

  Source: National Institutes of Health

• Vaccines work by introducing a harmless version of a germ so the immune system learns to recognize and fight it

  Source: Centers for Disease Control and Prevention