Pharmacology · chapter 6 · Introduction to the Immune System and the Inflammatory Response
Introduction to Immunity
The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.
Key points
What the immune system does
These components work in harmony to identify, neutralize, and eliminate foreign invaders by distinguishing between self and non-self and recognizing specific patterns found on the surface of a pathogen.
Innate immunity is always on
The innate immune system provides the first line of defense and is always “on.” It acts rapidly upon encountering pathogens (Justiz-Vaillant et al., 2022).
Parts of the innate system
It includes physical barriers like the skin, hair, and mucous membranes as well as certain white blood cells, such as basophils, mast cells, monocytes, neutrophils, and macrophages, that respond quickly to infections.
When adaptive immunity steps in
When a pathogen breaches the innate defenses, the adaptive immune system (also known as the acquired immune system) comes into play to control infection.
Adaptive immunity has memory
It is more specific to pathogens, has memory, and develops over time, through either encountering a pathogen or receiving a vaccination (Justiz-Vaillant et al., 2022).
T cells and B cells
T cells produce a cell-mediated immune response, and B cells produce the humoral immune response (as seen in Figure 6.3).
Plasma cells make antibodies
These activated B cells then undergo differentiation and proliferation to form plasma cells, which are specialized factories for producing antibodies.
Antibody levels peak in 1–2 weeks
The production of antibodies increases over time, reaching peak levels within 1 to 2 weeks after the initial encounter with the antigen.
Memory B cells
Memory B cells remember the encountered antigen and can rapidly initiate a strong response if the same antigen is encountered again in the future.
Helper T cells release cytokines
They release chemical signals (cytokines) that stimulate the proliferation and activation of other immune cells, including cytotoxic T cells and B cells.
Cytotoxic T cells kill abnormal cells
Cytotoxic T cells recognize cells that display foreign antigens on their surface, such as virus-infected cells or cancer cells. Cytotoxic T cells release toxic substances that attack and kill infected or abnormal cells, effectively eliminating the cells.
How vaccination works
This process forms the basis for vaccination, where the body is exposed to harmless versions of antigens to develop immunity without experiencing severe symptoms of the disease.
Antibodies take days to weeks
The process of antibody production and maturation takes a few days to weeks, but once antibodies are generated, they remain in the body as part of the immune memory.
Opsonization
Opsonization: Antibodies can coat pathogens, facilitating their recognition and uptake by phagocytic cells like macrophages and neutrophils, leading to their destruction (Thau et al., 2023).
Terms to know
- antigen
- An antigen is a molecule or molecular structure, typically a protein or polysaccharide, that is recognized by the immune system as foreign or non-self.
- Antibodies
- Antibodies, also known as immunoglobulins (Ig), are Y-shaped proteins produced by B cells in response to the presence of antigens (Aziz et al., 2023).
- Cell-mediated immunity
- Cell-Mediated Immunity Cell-mediated immunity is an immune response that involves T cells, specifically helper T cells (CD4 cells) and cytotoxic T cells (CD8 cells).
- complement cascade
- This reaction is also known as a complement cascade (Bardhan Kushik, 2023).
Practice questions
Stuck on select-all-that-apply? How to take them one option at a time.
The graded version needs JavaScript. Every question is below anyway, with the answer and why.
Every question here, with the answer
A nursing student asks which part of the immune system acts first when bacteria enter a small cut in the skin. What is the best answer?
- The innate immune system, which is always active and responds rapidly.
- Plasma cells, which reach peak antibody levels within minutes.
- Memory B cells, which form only after vaccination.
- Cytotoxic T cells, which are the first line of defense.
Answer: The innate immune system, which is always active and responds rapidly.
The innate immune system is the first line of defense, is always on, and acts rapidly. Memory B cells, cytotoxic T cells and plasma cells belong to the adaptive system, which comes into play after the innate defenses are breached, and antibody levels take 1 to 2 weeks to peak.
A client who received a vaccine yesterday asks why they are not protected right away. Which explanation by the nurse is accurate?
- The vaccine works only through the skin barrier.
- Antibody production increases over time and peaks within 1 to 2 weeks.
- Vaccines protect only after a second exposure to the real disease.
- Protection starts immediately but fades after one day.
Answer: Antibody production increases over time and peaks within 1 to 2 weeks.
After the first encounter with an antigen, antibody production rises over time and peaks within 1 to 2 weeks. The other options contradict the section: vaccination builds immunity without the disease, and antibodies stay as immune memory.
Which structures or cells are part of the innate immune system? Select all that apply.
- Neutrophils
- Plasma cells
- Mucous membranes
- Skin
- Memory B cells
Answer: Neutrophils, Mucous membranes, Skin
The innate system includes physical barriers such as skin, hair and mucous membranes plus quick-acting white cells such as neutrophils and macrophages. Memory B cells and plasma cells come from B cells in the adaptive (humoral) response.
A nurse is explaining why a person who had an infection once can fight it off faster the next time. Which cells are responsible?
- Basophils
- Mast cells
- Monocytes
- Memory B cells
Answer: Memory B cells
Memory B cells remain after the antigen is cleared and can rapidly start a strong response if the same antigen returns. Mast cells, basophils and monocytes are innate cells without antigen memory.
Which description of cytotoxic T cells should the nurse include when teaching about cell-mediated immunity?
- They coat pathogens so neutrophils can find them.
- They form the skin barrier.
- They produce antibodies against pollen.
- They kill virus-infected or cancer cells that display foreign antigens.
Answer: They kill virus-infected or cancer cells that display foreign antigens.
Cytotoxic T cells recognize cells showing foreign antigens, such as virus-infected or cancer cells, and release toxic substances that kill them. Antibodies are made by B cells, and coating pathogens is opsonization by antibodies.
When antibodies bind to antigens, which effects can result? Select all that apply.
- Agglutination of pathogens
- Formation of the skin barrier
- Activation of complement
- Opsonization of pathogens
- Neutralization of toxins
Answer: Agglutination of pathogens, Activation of complement, Opsonization of pathogens, Neutralization of toxins
The section lists neutralization, opsonization, agglutination and activation of complement as purposes of antigen-antibody binding. The skin is a physical barrier of the innate system, not a result of antibody binding.
Where every quote comes from
Section 6.1 Introduction to Immunity of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.
The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.