1. What is innate immunity?
a. Innate immunity, also called natural immunity, is the first line of
defense. This type of defense is in place before an infection takes
place and can function immediately. It is comprised of physical,
chemical, cellular, and molecular defenses.
2. How does the skin act as a physical barrier?
a. The skin’s design makes it a strong physical barrier. It has closely
packed cells in multiple layers that are continuously being shed.
Keratin covers the skin, which creates a salty, acidic environment
inhospitable to microbes. It also contains antimicrobial proteins and
lysozymes that inhibit microorganisms and help to destroy them.
3. What cells are involved in innate immunity?
a. They are dendritic cells, monocytes, macrophages, NK cells, and intraepithelial
lymphocytes, basophils, eosinophils, neutrophils
4. Describe each type of leukocyte and explain their function:
a. Neutrophils - use phagocytosis to kill microbes
b. Eosinophils - active in parasitic infections and allergic responses
c. Basophils - release histamine and proteolytic enzymes
d. Monocytes - engage in inflammatory response and phagocytize foreign
substances
e. Macrophages - first phagocyte that encounters organisms
5. Describe adaptive immunity:
a. Adaptive immunity, also called acquired immunity, is the second line
of defense and includes both humoral and cellular mechanisms that
respond to cell-specific substances known as antigens. Adaptive
immunity is acquired through previous exposure to infections and
other foreign agents. It can not only distinguish self from nonself but
can recognize and destroy specific foreign agents based on their
different antigenic properties. This response takes more time but is
extremely effective.
6. What are antigens?
a. Antigens are present on the surface of pathogens or other foreign
substances that elicit the adaptive immune response.
7. What are the primary cells of adaptive immunity?
a. Lymphocytes, antigen-presenting cells, and effector cells
8. Describe B & T lymphocytes and discuss their role in immunity:
a. B lymphocytes produce the antibodies (humoral immunity) and T
lymphocytes provide the cell-mediated immunity. B and T
lymphocytes have the unique function as the only cells to recognize
specific antigens present on the surface of pathogens and to
remember them in the future.
, Table 3.1 Features of innate and adaptive immunity
Feature Innate Adaptive
Time of Immediate (minutes/hours) Dependent upon exposure (first:
response delayed; second: immediate d/t
antibody production
Diversity Limited to classes or groups Very large; specific for each unique
of microbes antigen
Microbe General patterns on Specific to individual microbes and
recognition microbes; nonspecific antigens
Nonself Yes Yes
recognition
Response to Similar with each exposure Immunologic memory; more rapid
repeated and efficient with subsequent
infection exposure
Defense Epithelium (skin, mucous Cell killing; tagging of antigen by
membranes), phagocytes, antibody for removal
inflammation, fever
Cellular Phagocytes T and B lymphocytes, macrophages,
components (monocytes/macrophages, DCs, NK cells
neutrophils); NK cells, DCs
a. Innate immunity, also called natural immunity, is the first line of
defense. This type of defense is in place before an infection takes
place and can function immediately. It is comprised of physical,
chemical, cellular, and molecular defenses.
2. How does the skin act as a physical barrier?
a. The skin’s design makes it a strong physical barrier. It has closely
packed cells in multiple layers that are continuously being shed.
Keratin covers the skin, which creates a salty, acidic environment
inhospitable to microbes. It also contains antimicrobial proteins and
lysozymes that inhibit microorganisms and help to destroy them.
3. What cells are involved in innate immunity?
a. They are dendritic cells, monocytes, macrophages, NK cells, and intraepithelial
lymphocytes, basophils, eosinophils, neutrophils
4. Describe each type of leukocyte and explain their function:
a. Neutrophils - use phagocytosis to kill microbes
b. Eosinophils - active in parasitic infections and allergic responses
c. Basophils - release histamine and proteolytic enzymes
d. Monocytes - engage in inflammatory response and phagocytize foreign
substances
e. Macrophages - first phagocyte that encounters organisms
5. Describe adaptive immunity:
a. Adaptive immunity, also called acquired immunity, is the second line
of defense and includes both humoral and cellular mechanisms that
respond to cell-specific substances known as antigens. Adaptive
immunity is acquired through previous exposure to infections and
other foreign agents. It can not only distinguish self from nonself but
can recognize and destroy specific foreign agents based on their
different antigenic properties. This response takes more time but is
extremely effective.
6. What are antigens?
a. Antigens are present on the surface of pathogens or other foreign
substances that elicit the adaptive immune response.
7. What are the primary cells of adaptive immunity?
a. Lymphocytes, antigen-presenting cells, and effector cells
8. Describe B & T lymphocytes and discuss their role in immunity:
a. B lymphocytes produce the antibodies (humoral immunity) and T
lymphocytes provide the cell-mediated immunity. B and T
lymphocytes have the unique function as the only cells to recognize
specific antigens present on the surface of pathogens and to
remember them in the future.
, Table 3.1 Features of innate and adaptive immunity
Feature Innate Adaptive
Time of Immediate (minutes/hours) Dependent upon exposure (first:
response delayed; second: immediate d/t
antibody production
Diversity Limited to classes or groups Very large; specific for each unique
of microbes antigen
Microbe General patterns on Specific to individual microbes and
recognition microbes; nonspecific antigens
Nonself Yes Yes
recognition
Response to Similar with each exposure Immunologic memory; more rapid
repeated and efficient with subsequent
infection exposure
Defense Epithelium (skin, mucous Cell killing; tagging of antigen by
membranes), phagocytes, antibody for removal
inflammation, fever
Cellular Phagocytes T and B lymphocytes, macrophages,
components (monocytes/macrophages, DCs, NK cells
neutrophils); NK cells, DCs
