Immunity facts for kids

Your body is amazing! It has a special superpower called immunity. This means it can fight off things that try to make you sick, like infections from tiny germs. It also helps get rid of dust in your lungs and even fights bad cells.

Think of your immune system as your body's personal army. It protects you from 'invaders' that don't belong.

There are two main ways your body protects itself:

• Innate immunity: This is your body's first line of defense. It's like a general shield that protects you from many different germs right away. But it doesn't 'remember' specific germs, so it gives no long-term protection.
• Adaptive immunity: This is a smarter defense. It learns about specific germs and 'remembers' them. If the same germ tries to invade again, your body can fight it off much faster and stronger. This gives you long-term protection.

All living things, from animals and plants to fungi, have some form of innate immunity. Animals with backbones, like humans, also have adaptive immunity.

You can also get help for your immune system through vaccinations. A vaccination is usually an injection that contains a tiny, safe part of a virus or bacteria that causes a disease. When your body gets this vaccine, it learns how to fight that specific germ without getting sick. Then, if you meet the real germ later, your body is ready to defend itself quickly!

The Science of Immunity

Immunology is the science that studies how your immune system works. It looks at how your body protects itself from diseases. This field of study comes from medicine and early ideas about how people become immune to sickness.

Early Discoveries

One of the first times immunity was noticed was during the plague of Athens way back in 430 BC. A historian named Thucydides wrote that people who had already survived the plague could take care of sick people without getting sick again. This showed that their bodies had learned to fight off the disease.

In the 1700s, a scientist named Pierre-Louis de Maupertuis did experiments with scorpion venom. He saw that some dogs and mice were naturally protected from this venom.

Vaccines and Germs

Later, Louis Pasteur used these ideas to develop vaccinations. He also came up with the germ theory of disease. This theory said that tiny living things, called germs, cause diseases. This was a big change from older ideas, like the miasma theory, which thought bad air caused sickness.

It wasn't until 1891 that Robert Koch proved that tiny living things really do cause infectious disease. He even won a Nobel Prize for his work in 1905. Viruses were later confirmed as disease-causing agents in 1901, when the yellow fever virus was discovered by Walter Reed.

Modern Immunology

Near the end of the 1800s, immunology made huge progress. Scientists learned a lot about two important parts of immunity:

• Humoral immunity: This involves special proteins called antibodies. Antibodies float in your blood and help fight off germs.
• Cell-mediated immunity: This involves special cells, like T cells and dendritic cells, that directly attack infected cells or help other immune cells.

A very important scientist was Paul Ehrlich. He explained how antibodies are very specific and only react to certain germs. He shared a Nobel Prize in 1908 with Elie Mechnikov, who was a key figure in understanding how cells fight off infections.