1.
Which of the following substances stimulate the activity of NK cells?
Correct Answer
D. All of the above
Explanation
IFN-alpha, IFN-beta, and IL-12 are all substances that stimulate the activity of NK cells. IFN-alpha and IFN-beta are types of interferons that are released in response to viral infections and have immunomodulatory effects, including enhancing NK cell activity. IL-12 is a cytokine that plays a critical role in activating NK cells and promoting their cytotoxic functions. Therefore, all of these substances can enhance the activity of NK cells.
2.
Which of the following is an NK cell membrane marker?
Correct Answer
C. Integrin
Explanation
Integrin is an NK cell membrane marker. Integrins are a family of cell adhesion molecules that play a crucial role in the immune response. They are involved in the attachment of NK cells to target cells and facilitate the killing of these cells. Insulin, Titin, and Angiotensin are not NK cell membrane markers and do not have a direct role in NK cell function.
3.
Who discovered natural killer cells?
Correct Answer
B. Rolf Keissling
Explanation
Rolf Keissling is credited with the discovery of natural killer cells. He is a Swedish immunologist who first identified these cells in the 1970s. Natural killer cells are a type of white blood cell that play a critical role in the immune system's defense against viruses and cancer cells. Keissling's discovery has greatly contributed to our understanding of the immune response and has paved the way for further research in immunology.
4.
Where do NK cells differentiate in the body?
Correct Answer
D. Bone marrow
Explanation
NK cells, also known as natural killer cells, are a type of lymphocyte that plays a crucial role in the innate immune response. They are responsible for detecting and eliminating infected or cancerous cells. NK cells differentiate in the bone marrow, where they undergo maturation and acquire their functional properties. This process involves the expression of specific cell surface markers and the development of their cytotoxic abilities. Once differentiated, NK cells migrate to various tissues and organs throughout the body, where they can carry out their immune surveillance and defense functions.
5.
What is the basic structure of an NK cell?
Correct Answer
A. Large, granular
Explanation
NK cells, also known as natural killer cells, are a type of lymphocyte that play a crucial role in the immune system's defense against viral infections and tumor cells. The basic structure of an NK cell is characterized by its large size and granular appearance. These cells have abundant cytoplasm filled with granules containing various proteins and enzymes that aid in their cytotoxic activities. The large, granular structure of NK cells allows them to efficiently recognize and destroy infected or abnormal cells in the body.
6.
Which of the following activating receptors of the NK plays a role in antibody-dependent cell-mediated cytotoxicity?
Correct Answer
C. CD16
Explanation
CD16 is the correct answer because it is an activating receptor of the NK (Natural Killer) cells that plays a role in antibody-dependent cell-mediated cytotoxicity. CD16, also known as FcγRIII, is a receptor for the Fc portion of immunoglobulin G (IgG) antibodies. When IgG antibodies bind to target cells, CD16 on NK cells recognizes and binds to the Fc portion of the bound antibodies, leading to the activation of NK cells and subsequent killing of the target cells.
7.
When were NK cells discovered?
Correct Answer
A. 1975
Explanation
NK cells, also known as natural killer cells, were discovered in 1975. These cells are a type of lymphocyte that play a crucial role in the immune system's defense against cancer and viral infections. They are able to recognize and kill infected or abnormal cells without the need for prior activation, making them an important component of the body's innate immune response. The discovery of NK cells in 1975 marked a significant advancement in our understanding of the immune system and its mechanisms of defense.
8.
Which of the following molecules plays a crucial role in NK cell activation?
Correct Answer
B. Cytokines
Explanation
Cytokines play a crucial role in NK cell activation. Cytokines are small proteins that are secreted by various immune cells and act as chemical messengers to regulate immune responses. They can stimulate NK cell proliferation, enhance their cytotoxicity, and promote their activation and differentiation. By binding to specific receptors on NK cells, cytokines can trigger signaling pathways that lead to the activation of NK cells and their subsequent killing of infected or cancerous cells. Therefore, cytokines are essential for the proper functioning of NK cells in immune responses.
9.
How much percentage of lymphocytes do NK cells make up in the body?
Correct Answer
C. 5-10%
Explanation
NK cells, or natural killer cells, are a type of lymphocyte that play a crucial role in the immune system's defense against viruses and cancer cells. They are known for their ability to kill infected or abnormal cells without prior sensitization. While the exact percentage may vary among individuals, on average, NK cells make up approximately 5-10% of the total lymphocyte population in the body.
10.
Which of the following is true about NK cells?
Correct Answer
B. They do not have T or B cell receptors
Explanation
NK cells do not have T or B cell receptors. T and B cells are part of the adaptive immune response and have receptors that allow them to recognize specific antigens. In contrast, NK cells are part of the innate immune response and do not have these specific receptors. Instead, NK cells have receptors that recognize general patterns on infected or abnormal cells, allowing them to target and kill these cells.