Download Immune Response

BIOLOGY - Immunity Model – Activity
Period 1 2 3 4 5 6 7 8
Date: ________________
Station # _______
Names ________________
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Background:
Pathogens are disease-causing agents such as viruses and bacteria that disrupt or destroy the cells
of their host. The immune system is the body’s main defense against these invaders. The
immune system recognizes, attacks, destroys and “remembers” every type of pathogen that
enters the body. It does this through the production of specialized blood cells (B lymphocytes
and T lymphocytes) that communicate and coordinate their activities. The two main systems of
the immune response are cell-mediated immunity and humoral immunity. Cell-mediated
immunity destroys pathogen-infected body cells (and cancer cells). Humoral immunity destroys
free pathogens in the body fluids. The two systems are completely dependent on macrophages
and helper T-cells to initiate their responses. Both systems need to be activated for an effective
response to the invading pathogen. Each system leaves behind memory cells after each
encounter that allows the body to recognize and destroy the same pathogen more quickly if it
ever invades the body again.
Purpose: The purpose of this activity is to study the steps of the immune response.
Part I: Identifying the players.
Directions: The following characters all play a role in the immune response. Use your class
notes or textbook to record the role for each character in the table below.
Player
Pathogen
Antigens
Macrophage
Role
Helper T-cells
Killer T-cells
Plasma B-cells
Memory B-cells
Suppressor T-Cells
Memory T-Cells
Part II: The Primary Immune Response
The primary immune is the series of actions that occur in the body when a new pathogen (never
been seen before) invades. Both the cell-mediated and humoral responses are activated by
macrophages and helper T-cells.
Directions:
 Find the picture that matches the description for each step of the primary immune
response. Lines separate pictures belonging to different steps.
 Cut and glue the picture next to its description.
 Label any required diagrams.
1. Virus evades nonspecific immune defenses and invades the body.
2. Macrophage recognizes foreign antigens on the virus and engulfs the virus by phagocytosis.
(Label macrophage, antigens and virus)
3. Virus is digested by lysosomes inside the macrophage. Viral antigens are displayed on the
surface of the macrophage.
4. Macrophage releases chemicals that attract helper T-cells.
5. Helper T-cells migrate to the macrophage. A helper T-cell receptor binds to the antigens
displayed on the macrophage to “learn” the antigen.
6. The helper T-cell divides to produce: more helper T-cells (identical to itself), killer T-cells,
Memory T-cells and suppressor T-cells
7a. Helper T-cells activate B-cells that produce
complementary antibody to antigen.
membrane
8. B-cells divide to produce plasma B-cells and
Memory B-cells.
7b. Killer T-cells destroy body cells infected
With virus by disrupting the cell
9. Plasma B-cells produce antibodies that bind to
And Neutralize the antigens, disabling the virus.
10. Suppressor T-cells shut the response off when all free viruses and viral-infected cells have
been destroyed.
11. Memory B-cells and Memory T-cells remain for future encounters with the same pathogen.
Analysis:
1. What is the difference between cell-mediated and humoral immunity?
2. Which two cells are crucial to activating the cell-mediated and humoral responses?
3. List all the steps that are part of the humoral response. (Provide the number and letter for as
many steps that apply.)
4. List all the steps that are part of the cell-mediated response. (Provide the number and letter
for as many steps that apply.)
5. The HIV virus infects and impairs the helper T-cells of the immune system. Do you think a
person with AIDS is able to generate an adequate cell-mediated and humoral response to new
pathogens? Why or why not?
6. Why does an individual show symptoms of the pathogen during the primary response, but not
the secondary response?
7. What is the relationship between the shape of the antibodies produced by the plasma B-cells
and their corresponding antigens?
Primary Response
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