1. 4-2 Introduction to the Immune System Student Power Point

2. Specific Immune Response
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3. Specific Immune Response
What does “specific” mean anyways?
“Specific” is someone or something that is specially suited for a purpose or need.
An example of “specific” is someone saying exactly which shoes they want someone to grab for them. Ex: I want that specific pair of shoes. The black sneakers with blue laces.

4. Specific Immune Response
A specific immune response involves…
Antigens (bad guys) and antibodies (good guys)

5. In daily life we might speak of viruses, bacteria, and toxins
In daily life we might speak of viruses, bacteria, and toxins. However, when reading about the immune system you’ll often come across the words antigen and pathogen.
An antigen is a foreign substance that triggers a reaction from the immune system. Antigens are often found on the surfaces of bacteria and viruses.
A pathogen is a microscopic organism that causes sickness. Hostile bacteria and viruses are examples of pathogens.

6. Specific Immune Response
What happens when a bacteria of virus infects your body?
White Blood Cell (in purple) Releasing Antibodies
Some white blood cells make a specific protein, called an antibody, that will respond to an antigen. Antibodies are released from the white blood cells so that they can seek out intruders and help destroy them. White blood cells produce antibodies at an amazing rate and can release tens of thousands of antibodies per second.

7. Specific Immune Response
What happens once a bacteria or virus is “tagged” by an antibody?
Different Type of White Blood Cell (in green) Eats the “Tagged” Bacteria
When the Y-shaped antibody finds a matching antigen, it attaches to it. The attached antibodies serve as an appetizing coating for eater cells such as the macrophage (a white blood cell that eats pathogens).

8. Antibodies also neutralize toxins and viruses, preventing them from infecting new cells. Each branch of the Y-shaped antibody can bind to a specific antigen, so while one branch binds to an antigen on one pathogen cell, the other branch could bind to another cell - in this way pathogens are gathered into larger groups that are easier for macrophages to eat.