1.
Antigen-presenting cells (APCs) include macrophages and dendritic cells, which are found in lymphoid tissues and the____. These are critical in the uptake and presentation of antigens to T cells.
Correct Answer
D. Skin
Explanation
APCs, such as macrophages and dendritic cells, are found in lymphoid tissues and the skin. They play a crucial role in capturing and presenting antigens to T cells, which is essential for the immune response. The skin is the largest organ in the body and acts as a physical barrier against pathogens. It contains a large number of APCs that constantly survey the environment for potential antigens. When they encounter antigens, they capture and process them, presenting them to T cells to initiate an immune response. Therefore, the skin is an important site for antigen presentation and immune surveillance.
2.
How many doses of the Hepatitis B vaccine (5µg HBsAg in 0.5mL intramuscular) are required to reach a protective level of antibody?
Correct Answer
C. 3
Explanation
To reach a protective level of antibody, it is typically recommended to administer three doses of the Hepatitis B vaccine. Each dose contains 5µg of HBsAg in 0.5mL intramuscular. Therefore, a total of three doses are required to ensure sufficient protection against Hepatitis B.
3.
Match the following innate immune system cell types with their function: Macrophages
Correct Answer
A. pHagocytosis and bacteriocidal mechanisms, antigen presentation
Explanation
Macrophages are a type of innate immune system cell that are responsible for phagocytosis and bacteriocidal mechanisms, meaning they engulf and destroy pathogens. They also play a role in antigen presentation, which is the process of displaying antigens to activate the adaptive immune response. This allows the immune system to recognize and respond to specific pathogens.
4.
Match the following innate immune system cell types with their function: Tissue mast cells
Correct Answer
D. Release of histamine and other mediators
Explanation
Tissue mast cells play a key role in the inflammatory response by releasing histamine and other mediators, which are involved in inflammation and allergic reactions. This function helps initiate the immune response to various pathogens and allergens.
5.
Match the following innate immune system cell types with their function: Natural killer cells
Correct Answer
B. Lysis of some virally infected cells
Explanation
Natural killer cells are a type of innate immune system cell that is responsible for the lysis (destruction) of some virally infected cells. They recognize and kill cells that are infected with viruses, helping to prevent the spread of the infection. This is an important function of the innate immune system in defending the body against viral infections.
6.
Match the following innate immune system cell types with their function: Neutrophils
Correct Answer
E. pHagocytosis and bacteriocidal mechanisms
Explanation
Neutrophils are a type of innate immune system cell that are responsible for phagocytosis and bacteriocidal mechanisms. They engulf and destroy pathogens through phagocytosis, which involves engulfing the pathogens and breaking them down. Neutrophils also release bacteriocidal substances to kill the pathogens. This function helps to eliminate and control infections in the body.
7.
T cells are made in the____ and complete their differentiation in the____.
Correct Answer
D. Bone marrow; Thymus
Explanation
T cells, a type of white blood cell involved in immune responses, are produced in the bone marrow and then migrate to the thymus gland to complete their differentiation. The bone marrow is responsible for the initial production of T cell precursors, while the thymus provides the necessary environment for their maturation and development into functional T cells.
8.
In a resting lymphocyte, B cells and T cells can be distinguished from each other via a simple blood smear.
Correct Answer
B. False
Explanation
In a resting lymphocyte, B cells and T cells cannot be distinguished from each other via a simple blood smear. Both B cells and T cells look similar in appearance and cannot be differentiated based on their morphology alone. Additional tests, such as flow cytometry or immunohistochemistry, are required to accurately distinguish between B cells and T cells.
9.
Which of the following is a transmembrane glycoprotein that serves as a co-receptor for the T cell receptor (TCR), and is also known as a cytotoxic T cell (CTL)?
Correct Answer
B. Cluster of differentiation 8 (CD8+)
Explanation
CD8+ is a transmembrane glycoprotein that acts as a co-receptor for the T cell receptor (TCR) on cytotoxic T cells. It plays a crucial role in the activation of T cells and the immune response. CD8+ binds to major histocompatibility complex class I (MHC-I) molecules on antigen-presenting cells, which allows the TCR to recognize and respond to specific antigens. This interaction enhances the binding affinity between the T cell and the target cell, leading to the activation of cytotoxic T cells and the destruction of infected or abnormal cells.
10.
Which of the following produce large amounts of antibodies (Igs) and differentiate
upon stimulation from CD4+ cells?
Correct Answer
C. Plasma cells (activated B cells)
Explanation
Plasma cells (activated B cells) produce large amounts of antibodies (Igs) and differentiate upon stimulation from CD4+ cells. CD4+ cells play a crucial role in activating B cells and promoting antibody production. CD8+ cells are primarily involved in cytotoxic immune responses and do not produce antibodies. Hence, the correct answer is plasma cells (activated B cells).
11.
Which of the following is a glycoprotein expressed on the surface of T helper cells,
regulatory T cells, monocytes, macrophages, and dendritic cells?
Correct Answer
A. Cluster of differentiation 4 (CD4+)
Explanation
CD4 is a glycoprotein that is expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells. It plays a crucial role in the immune response by binding to major histocompatibility complex class II (MHC-II) molecules on antigen-presenting cells. This interaction helps in the activation of T cells and the initiation of an immune response. CD4 is also the primary receptor for the human immunodeficiency virus (HIV), allowing the virus to enter and infect CD4+ T cells. Therefore, CD4 is an important marker for identifying and studying these immune cell populations.
12.
Match the following innate immune system cell types with their function: Eosinophils
Correct Answer
C. Killing parasites
Explanation
Eosinophils are a type of innate immune system cell that are primarily responsible for killing parasites. They do this by releasing toxic granules that target and kill parasites. Eosinophils are not involved in phagocytosis and bacteriocidal mechanisms like other immune cells such as neutrophils and macrophages. They also do not play a role in lysing virally infected cells. Instead, eosinophils are specifically specialized in combating parasitic infections. Additionally, eosinophils can also release histamine and other mediators, which can contribute to allergic reactions and inflammation.
13.
Match the stage of an adaptive (acquired) immune response with the description: Proliferation of cells with matching receptors
Correct Answer
B. Activation pHase
Explanation
The activation phase of an adaptive immune response refers to the stage where immune cells, such as T and B cells, are activated upon encountering an antigen. During this phase, these cells undergo proliferation, meaning they multiply in number, to generate a larger population of cells with matching receptors. This increased cell population allows for a more effective immune response against the antigen. The cognitive phase refers to the initial recognition and processing of the antigen, while the effector phase involves the elimination of the antigen. "None of these" is not the correct answer as it does not match any of the stages described.
14.
Match the stage of an adaptive (acquired) immune response with the description: Eventual elimination of antigen
Correct Answer
C. Effector pHase
Explanation
The effector phase of an adaptive immune response is characterized by the eventual elimination of the antigen. During this phase, the immune system responds to the presence of the antigen by producing specific antibodies and activating immune cells to directly attack and eliminate the antigen. This phase is crucial in effectively clearing the infection or eliminating the foreign substance from the body.
15.
Humoral immunity is mediated by antibodies from____ and is involved in the elimination of____ pathogens. Cell-mediated immunity is mediated by____ and is involved in the elimination of____ pathogens.
Correct Answer
B. B lympHocytes; Extracellular; T lympHocytes; Intracellular
Explanation
Humoral immunity is mediated by antibodies produced by B lymphocytes and is involved in the elimination of extracellular pathogens. Cell-mediated immunity is mediated by T lymphocytes and is involved in the elimination of intracellular pathogens.
16.
Match the stage of an adaptive (acquired) immune response with the description: Recognition of antigen
Correct Answer
A. Cognitive pHase
Explanation
The cognitive phase of an adaptive immune response refers to the initial recognition of antigens by immune cells. During this phase, immune cells such as B cells and T cells encounter antigens and begin to process and present them to other immune cells. This recognition is crucial for the immune system to initiate a targeted response against the specific antigen.
17.
Which of the following is NOT a major feature (characteristic) of the adaptive immune system?
Correct Answer
E. Speed
Explanation
Speed is not a major feature of the adaptive immune system. The adaptive immune system is known for its specificity, diversity, memory, and ability to improve over time. However, speed is not considered a primary characteristic of the adaptive immune system. While the adaptive immune response can be efficient and effective, it is generally slower compared to the innate immune response, which provides immediate, non-specific defense against pathogens.
18.
What stage of an adaptive immune response involves secretion of antibody from a large plasma cell with extensive endoplasmic reticulum?'
Correct Answer
C. Effector pHase
Explanation
The effector phase of an adaptive immune response involves the secretion of antibodies from large plasma cells that have extensive endoplasmic reticulum. During this phase, the immune system is actively fighting against the pathogen or antigen, and the antibodies produced by the plasma cells help to neutralize or eliminate the foreign invader. This is different from the cognitive and activation phases, which involve the recognition and initiation of the immune response, respectively. Therefore, the correct answer is the effector phase.
19.
Which of the following types of antigen-presenting cells (APCs) is critical in the uptake and presentation of antigen to T cells?
Correct Answer
B. Dendritic cell
Explanation
Dendritic cells are critical in the uptake and presentation of antigens to T cells. They are specialized APCs that capture and process antigens, and then present them to T cells to initiate an immune response. Dendritic cells have a unique ability to efficiently capture antigens from their surroundings and present them to T cells, making them a crucial link between innate and adaptive immunity. Macrophages and B cells also have antigen-presenting capabilities, but dendritic cells are particularly specialized for this function.
20.
Which of the following types of antigen-presenting cells (APCs) has immunoglobulin that functions as a receptor, then the antigen is internalized, degraded, and presented to T cells?
Correct Answer
C. B cell
Explanation
B cells are a type of antigen-presenting cell (APC) that have immunoglobulin receptors on their surface. When a B cell encounters an antigen that matches its specific receptor, the antigen is internalized, degraded, and presented to T cells. This process allows for the activation of T cells and the initiation of an immune response. Macrophages and dendritic cells also function as APCs, but they do not have immunoglobulin receptors on their surface. Therefore, the correct answer is B cell.
21.
Which of the following types of antigen-presenting cells (APCs) is specialized for
degradation and presentation of particulate antigens to T cells?
Correct Answer
A. MacropHage
Explanation
Macrophages are specialized antigen-presenting cells that have the ability to phagocytose (engulf) and degrade particulate antigens. They can then present the degraded antigens on their cell surface using major histocompatibility complex (MHC) molecules to activate T cells. Macrophages are found in various tissues and play a crucial role in the immune response by recognizing and eliminating foreign particles or pathogens. Dendritic cells and B cells also have antigen-presenting capabilities, but they are not specifically specialized for degradation and presentation of particulate antigens like macrophages.