1. Vaccine Education Module: The Immune System Updated: February 2015

2. Roles of the Immune System
The immune system protects the body by:
Recognizing the presence of infection
Containing the infection and working to eliminate it
Regulating itself so it does not damage the body
Remembering pathogens to prevent diseases from recurring

3. Components of the immune system
Dynamic communication network made up of:
Cells
Tissues
Organs

4. Organs of the Immune System
Spleen
Peyer’s patches
Appendix
Bone marrow
Tonsils
Adenoid glands
Thymus
Lymph nodes
Lymphatic vessels

5. Pathogens Organisms that can cause disease: Bacteria Viruses Parasites
Fungi
Most pathogens are so small that they must be viewed with a powerful electron microscope. Due to their microscopic size, these organisms are called microscopic. The study of microscopic organisms is called microbiology.

6. Example of a Type of Bacteria
This colorized scanning electron micrograph depicts Legionella pneumophila, the bacteria that causes Legionnaires’ disease.
Example of a Type of Bacteria
Courtesy CDC, Public Health Image Library (PHIL)

7. Example of a Type of Bacteria
This scanning electron micrograph (SEM) shows a strain of Staphylococcus aureus bacteria taken from a vancomycin intermediate resistant culture (VISA).
Example of a Type of Bacteria
Courtesy CDC

8. Influenza virus
Influenza Virus
Photo Credit: Cynthia Goldsmith, CDC

9. Measles Virus
Photo Credit: Cynthia Goldsmith, CDC

10. Five Types of White Blood Cells
Neutrophils: Phagocytose bacteria and fungi
Eosinophils: Kill parasites, destroy cancer cells and are involved in allergic reactions
Basophils: Release histamine and act in blood clotting
Monocytes: Become macrophages; digest dead or damaged cells and pathogens
Lymphocytes: Two major classes of these white blood cells
T cells
B cells

11. White Blood Cells Courtesy CDC, PHIL
This stained photomicrograph revealed a number of white blood cells otherwise known as leukocytes. These cells are part of the body’s antibody-mediated response, fighting the constant onslaught of pathogenic invaders such as bacteria and foreign debris.
White Blood Cells
Courtesy CDC, PHIL

12. White Blood Cell Courtesy CDC, PHIL
This scanning electron micrograph (SEM) depicted a number of red blood cells magnified 7766x. The cell in the center displaying a knobby surface is a white blood cell.
White Blood Cell
Courtesy CDC, PHIL

13. T Cells Activate B cells to produce antibodies
Activate macrophages to destroy antigens that have been tagged by antibodies
Kill our own cells that are infected with viruses

14. B Cells Produced in the bone marrow
Primary role is to produce antibodies

15. Antibodies Y-shaped molecules with two distinct regions
Constant region
Variable region allows different antibodies to recognize different antigens

16. Antibodies
Proteins that neutralize antigens and prepare them for destruction by phagocytes
Programmed to recognize and bind to the antigen so that it can be destroyed
Activate a group of proteins called complement, which assist in killing pathogens