1. KEY CONCEPT The immune system has many responses to pathogens and foreign cells.

2. Many body systems work to produce nonspecific responses.
Nonspecific responses are the same for every pathogen.
In inflammation, blood vessels become leaky.
white blood cells move toward infection and damaged tissue
capillary wall
extracellular space
white blood cell
characterized by swelling, redness, and pain

3. In fever, body temperature increases.
Low fevers stimulate white blood cells to mature.
High fevers can cause seizure, brain damage, and even death.

4. Cells of the immune system produce specific responses.
Specific immune responses begin with the detection of antigens.
Antigens are surface proteins on pathogens.
Each pathogen has a different antigen.
virus
antigens

5. There are two specific immune responses.
Cellular immunity uses T cells to destroy infected body cells.
pathogen
antigens
T cell
receptors
activated T cells
memory T cells

6. There are two specific immune responses.
Humoral immunity uses B cells to produce antibodies.
B cell
T cell
pathogen
memory B cells
activated B cells
antibodies

7. Both responses produce memory cells.
B cell
T cell
specialized T and B cells
provide acquired (active) immunity

8. The immune system rejects foreign tissues.
Tissue rejection occurs in organ or tissue transplants.
Tissue rejection is the result of an immune response.
immune system detects protein markers on the donor tissue
makes antibodies against the donor’s tissue