1.
Which of the following are involved in both innate and acquired immune responses?
Correct Answer
C. MacropHages
Explanation
Macrophages are involved in both innate and acquired immune responses. In the innate immune response, macrophages act as the first line of defense by engulfing and destroying pathogens. They also produce inflammatory molecules to recruit other immune cells. In the acquired immune response, macrophages present antigens to T cells, activating them and initiating a specific immune response. Therefore, macrophages play a crucial role in both the initial non-specific response and the subsequent adaptive response to infections.
2.
Select the true statementsfor IgG.
Correct Answer(s)
A. Most abundant and most potent antibody
D. Roles of agglutination, precipitation, and opsonization
E. Conferral of immunity to fetus
F. Antibody dependent cell-mediated cytotoxicity
H. Present most places, including lympH, blood, csf, and peritoneal fluid
Explanation
IgG is the most abundant and most potent antibody in the body. It plays a role in agglutination, precipitation, and opsonization, which are important immune responses. IgG also confers immunity to the fetus, as it can pass through the placenta from the mother to the fetus. Additionally, IgG is involved in antibody-dependent cell-mediated cytotoxicity, where it binds to target cells and activates immune cells to destroy them. IgG is present in most places in the body, including lymph, blood, cerebrospinal fluid, and peritoneal fluid.
3.
IgM is the first antibody produced, with elevated levels indicating recent infection.
Correct Answer
A. True
Explanation
IgM is indeed the first antibody produced by the immune system in response to an infection. It is a marker of recent infection because it is produced in the early stages of an immune response. As the infection progresses, the levels of IgM decrease and other antibodies like IgG are produced. Therefore, elevated levels of IgM indicate that the infection is recent.
4.
IgM is too large to cross the placenta and is therefore synthesized by the placenta for protection of the fetus.
Correct Answer
A. True
Explanation
IgM is a type of antibody that is too large to cross the placenta. Therefore, it cannot be directly transferred from the mother to the fetus. To provide protection to the fetus, the placenta synthesizes IgM antibodies. This is true because IgM antibodies are important for the immune defense of the fetus against infections.
5.
Which of the following classes of antibody have the best agglutination and complement activation activity?
Correct Answer
B. IgM
Explanation
IgM antibodies have the best agglutination and complement activation activity. IgM is the first antibody produced during an immune response and it is typically present in higher concentrations in the early stages of an infection. IgM antibodies are able to bind to multiple antigens at the same time, leading to agglutination or clumping of the antigens. Additionally, IgM antibodies are very efficient in activating the complement system, which is a group of proteins that work together to destroy pathogens.
6.
What is the primary function of IgD?
Correct Answer
A. Differentiation/maturation of B cells
Explanation
IgD is primarily involved in the differentiation and maturation of B cells. It plays a crucial role in the activation of B cells and their development into antibody-producing plasma cells. IgD is expressed on the surface of mature B cells along with IgM, and it helps in the recognition of antigens and initiation of immune responses. This function of IgD is essential for the proper functioning of the immune system and the production of specific antibodies against pathogens.
7.
Antibodies present in one of the following two forms: free in circulation or bound to some cell.
Correct Answer
A. True
Explanation
Antibodies can exist in two forms: free in circulation or bound to a cell. This means that antibodies can either be floating freely in the bloodstream or attached to the surface of a cell. Therefore, the statement "Antibodies present in one of the following two forms: free in circulation or bound to some cell" is true.
8.
B and T cells both originate in the bone marrow, but B cells develop in the thymus, whereas T cells differentiate in the fetal liver and adult bone marrow.
Correct Answer
B. False
Explanation
B and T cells both originate in the bone marrow, but B cells develop in the bone marrow itself, while T cells differentiate in the thymus.
9.
Where are T cells educated to differentiate between self and non-self? This differentiation comes in the form of a T Cell Receptor.
Correct Answer
B. Thymus
Explanation
T cells are educated to differentiate between self and non-self in the thymus. The thymus is a specialized organ of the immune system where T cells mature and undergo a process called positive and negative selection. During this process, T cells that recognize self-antigens too strongly or not at all are eliminated, ensuring that only T cells capable of recognizing foreign antigens are allowed to leave the thymus and enter the bloodstream. This education is crucial for the proper functioning of the immune system and the prevention of autoimmune diseases.
10.
The presence of a T Cell Receptor differentiates a T cell from a B cell.
Correct Answer
A. True
Explanation
The presence of a T Cell Receptor is a key characteristic that distinguishes T cells from B cells. T cells are a type of white blood cell that play a crucial role in the immune response. They are responsible for recognizing and binding to specific antigens present on infected cells or foreign substances. The T Cell Receptor is a protein found on the surface of T cells that allows them to recognize and bind to these antigens. B cells, on the other hand, have B Cell Receptors that are responsible for recognizing and binding to antigens in a different way. Therefore, the presence of a T Cell Receptor is a defining feature of T cells.
11.
T Cell Receptors are rarely associated with CD3 Receptors on T Cells.
Correct Answer
B. False
Explanation
T Cell Receptors are commonly associated with CD3 Receptors on T Cells. The CD3 complex is an essential component of the T Cell Receptor, helping to transmit signals into the T cell when the receptor binds to an antigen. This association is crucial for T cell activation and the initiation of an immune response. Therefore, the statement that T Cell Receptors are rarely associated with CD3 Receptors is incorrect.
12.
The vast majority of T Cells contain which version of T Cell Receptor?
Correct Answer
TCR2
13.
Antigens must be processed by antigen presenting cells to be recognized by T Cells.
Correct Answer
A. True
Explanation
Antigens must be processed by antigen presenting cells in order for T cells to recognize them. This is because antigen presenting cells break down antigens into smaller fragments and present them on their surface, which allows T cells to bind to the antigen fragments and initiate an immune response. Without this processing step, T cells would not be able to recognize antigens and mount an immune response against them. Therefore, the statement is true.
14.
Antigen presenting cells are required to present antigens to T cells, but not B cells.
Correct Answer
A. True
Explanation
Antigen presenting cells play a crucial role in the immune response by presenting antigens to T cells, which then activate the immune system. This interaction is essential for the activation and regulation of T cells. On the other hand, B cells have their own unique mechanism for recognizing antigens and do not require antigen presenting cells for activation. Therefore, the statement that antigen presenting cells are required to present antigens to T cells, but not B cells, is true.
15.
B cells and T cells recognize antigens in much the same manner.
Correct Answer
B. False
Explanation
B cells and T cells do not recognize antigens in the same manner. B cells recognize antigens directly on their surface through B cell receptors, while T cells recognize antigens presented on the surface of other cells through T cell receptors. This difference in antigen recognition is a fundamental distinction between these two types of immune cells.
16.
Viral infection is the most potent natural signal for the synthesis of which of the following cytokines?
Correct Answer
C. INFa+b
Explanation
Viral infection is known to stimulate the synthesis of interferon alpha and beta (INFa+b). These cytokines play a crucial role in the body's immune response to viral infections by activating immune cells and inhibiting viral replication. INFa+b also help in the production of other cytokines and enhance the overall antiviral defense mechanism. Therefore, INFa+b is the most potent natural signal for the synthesis of these cytokines during viral infections.
17.
Type I Interferons, mediators of natural immunity, have which of the following as their principal biologic actions?
Correct Answer(s)
A. Inhibition of viral replication
B. Inhibition of cell proliferation
C. Increasing lytic potential of natural killer cells
D. Regulation of MHC I and II expression
Explanation
Type I Interferons have multiple biologic actions, including the inhibition of viral replication, inhibition of cell proliferation, increasing the lytic potential of natural killer cells, and regulation of MHC I and II expression. These actions contribute to the immune response against viral infections by limiting viral replication, suppressing the growth of infected cells, enhancing the killing ability of natural killer cells, and facilitating antigen presentation to T cells.
18.
TNFa responds primarily to which of the following?
Correct Answer
B. Gram-Negative Bacteria
Explanation
TNFa primarily responds to Gram-Negative Bacteria. TNFa, or Tumor Necrosis Factor-alpha, is a cytokine produced by various cells in the immune system. It plays a crucial role in the inflammatory response and is involved in the defense against bacterial infections. Gram-Negative Bacteria have a unique outer membrane that contains lipopolysaccharides (LPS), which can trigger the release of TNFa. This cytokine helps to activate immune cells, promote inflammation, and enhance the immune response against Gram-Negative Bacteria.
19.
TNFa is most like which of the following interleukins?
Correct Answer
A. IL-1
Explanation
TNFa is most like IL-1 because both are pro-inflammatory cytokines that play a role in immune responses and inflammation. They share similar functions and signaling pathways, and can both induce the production of other cytokines and chemokines. Additionally, TNFa and IL-1 are both involved in the regulation of fever and acute phase responses.
20.
Colony Stimulating Factors are commonly used for which of the following indications?
Correct Answer(s)
A. Prevention of chemotherapy-induced neutropenia
B. Stimulation of haemopoiesis in marrow failure
C. Promotion of cell differentiation
D. Assisting marrow transplantation
E. Augmentation of effector cell function
F. Stimulation of monocyte's anticancer effects
Explanation
Colony Stimulating Factors are commonly used for various indications including prevention of chemotherapy-induced neutropenia, stimulation of haemopoiesis in marrow failure, promotion of cell differentiation, assisting marrow transplantation, augmentation of effector cell function, and stimulation of monocyte's anticancer effects. These factors help in boosting the production and function of different types of blood cells, such as neutrophils, monocytes, and lymphocytes, which are important for the immune system and overall health.