Diseases Of Immunity
Questions are based on Chapter 6 of Robbins and Cotran Pathologic Basis of Disease 7th edition.
Questions and Answers
- 1.
Which of the following exhibit Toll like receptors? (6)
- A.
Macrophages
- B.
Erythrocytes
- C.
Neutrophils
- D.
Basophils
- E.
T cells
- F.
B cells
- G.
Plasma cells
- H.
Dendritic cells
- I.
Mucosal epithelial cells
- J.
Endothelial cells
- K.
Natural killer cells
Correct Answer(s)
A. Macrophages
C. Neutrophils
H. Dendritic cells
I. Mucosal epithelial cells
J. Endothelial cells
K. Natural killer cellsExplanation
These cells participate in the innate immune responseRate this question:
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- 2.
The Gram Negative LPS/LBP complex facilitates LPS binding to which molecule? _ _ _ _
Correct Answer(s)
CD14Explanation
The Gram Negative LPS/LBP complex facilitates LPS binding to CD14. CD14 is a glycoprotein found on the surface of various immune cells, including macrophages and dendritic cells. It acts as a receptor for lipopolysaccharide (LPS), a component of the outer membrane of Gram-negative bacteria. The LPS/LBP complex helps to deliver LPS to CD14, initiating an immune response and triggering the release of pro-inflammatory cytokines.Rate this question:
- 3.
Which is the most significant of the transcription factors activated by signalling from toll like receptors?
- A.
MECP2
- B.
NF-ÎşB
- C.
FOXP3
Correct Answer
B. NF-ÎşBExplanation
NF-ÎşB is the most significant transcription factor activated by signaling from toll-like receptors. Toll-like receptors play a crucial role in the innate immune response by recognizing pathogen-associated molecular patterns. Upon activation, toll-like receptors initiate a signaling cascade that leads to the activation of NF-ÎşB. NF-ÎşB then translocates to the nucleus and regulates the expression of genes involved in inflammation, immune response, and cell survival. Therefore, NF-ÎşB is considered the most significant transcription factor in mediating the immune response triggered by toll-like receptor signaling.Rate this question:
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- 4.
T_ _l l_ _e r_ _ _ _ _ _r activation ultimately results in synthesis of many different components of the innate immune response including cytokines, endothelial adhesion molecules and nitric oxide synthase.
Correct Answer
Toll like receptorExplanation
Toll-like receptors (TLRs) are a type of protein receptor found on the surface of immune cells. When activated, TLRs initiate a signaling cascade that leads to the synthesis of various components of the innate immune response, such as cytokines, endothelial adhesion molecules, and nitric oxide synthase. This activation is crucial for the immune system to mount an appropriate response against pathogens and maintain immune homeostasis. TLRs recognize specific patterns on pathogens, known as pathogen-associated molecular patterns (PAMPs), and play a crucial role in initiating the immune response.Rate this question:
- 5.
Mannose binding lectin and C-reactive protein are circulating plasma proteins, both of which coat microbes for _ _ _ _ _ _ _ _ _ _ _ _ and complement activation.
Correct Answer
phagocytosisExplanation
Mannose binding lectin and C-reactive protein are circulating plasma proteins that coat microbes for phagocytosis and complement activation. Phagocytosis is the process by which immune cells engulf and destroy foreign particles, such as microbes. By coating the microbes, mannose binding lectin and C-reactive protein facilitate their recognition and uptake by phagocytes, enhancing the immune response against the invading pathogens. This process is essential for the clearance of pathogens from the body and the activation of the complement system, which further enhances the immune response.Rate this question:
- 6.
Cell mediated (or cellular) immunity is responsible for defence against _ _ _ _ _ _ _ _ _ _ _ _ microbes.
Correct Answer
intracellularExplanation
Cell mediated (or cellular) immunity is responsible for defense against intracellular microbes. This means that this type of immune response is specifically designed to target and eliminate microbes that are able to invade and replicate within the cells of the body. Intracellular microbes include viruses, bacteria, and parasites that can infect and survive inside host cells. Cell mediated immunity involves the activation of T cells, which recognize and destroy infected cells, preventing the spread of the infection. This type of immunity is crucial in combating intracellular pathogens and preventing the development of severe infections.Rate this question:
- 7.
Humoral immunity protects against _ _ _ _ _ _ _ _ _ _ _ _ microbes and their _ _ _ _ _ _. (separate answers with a comma)
Correct Answer
extracellular, toxinsExplanation
Humoral immunity is a type of immune response that involves the production of antibodies. It is primarily responsible for protecting against extracellular microbes, which are pathogens that exist outside of cells. These microbes can include bacteria, fungi, and parasites. Additionally, humoral immunity also targets toxins, which are harmful substances produced by certain microbes. By neutralizing these toxins and preventing their harmful effects, humoral immunity plays a crucial role in defending the body against infection.Rate this question:
- 8.
T lymphocytes mediate _ _ _ _ _ _ _ _ immunity.
Correct Answer
cellularExplanation
T lymphocytes mediate cellular immunity. This type of immunity involves the direct action of T cells, which are a type of white blood cell, in recognizing and destroying infected or abnormal cells in the body. T lymphocytes play a crucial role in the immune response by coordinating and regulating the actions of other immune cells. They are able to recognize specific antigens and activate immune responses to eliminate pathogens or abnormal cells. Cellular immunity is important for defense against intracellular pathogens, such as viruses and certain bacteria, as well as for surveillance and elimination of cancer cells.Rate this question:
- 9.
B lymphocytes mediate _ _ _ _ _ _ _ immunity.
Correct Answer
humoralExplanation
B lymphocytes mediate humoral immunity. Humoral immunity refers to the immune response that involves the production of antibodies by B lymphocytes. These antibodies are released into the body fluids, such as blood and lymph, to neutralize or eliminate pathogens. B lymphocytes, also known as B cells, are a type of white blood cell that plays a crucial role in the adaptive immune response. They recognize and bind to specific antigens, triggering the production and release of antibodies. This immune response is called humoral immunity because it involves the action of antibodies in the body fluids.Rate this question:
- 10.
As well as being found in the blood, naive T cells are found in the _ _ _ _ _ _ _ _ _ _ _ _ areas of lymph modes and _ _ _ _ _ _ _ _ _ _ _ _ _ _ sheaths of the spleen. (separate answers with a comma)
Correct Answer
paracortical, periarteriolarExplanation
Naive T cells are found in the paracortical areas of lymph nodes and periarteriolar sheaths of the spleen. These specific locations within the lymph nodes and spleen are where naive T cells are primarily located. The paracortical areas are regions within the lymph nodes that are adjacent to the cortex, while the periarteriolar sheaths are found around the arterioles in the spleen. The presence of naive T cells in these areas is important for their activation and initiation of immune responses.Rate this question:
- 11.
What does CD in CD4 stand for? (3 words)
Correct Answer
cluster of differentiationExplanation
CD in CD4 stands for cluster of differentiation. This term refers to a group of cell surface molecules that are used to identify and classify different types of immune cells. CD4 specifically refers to a protein found on the surface of helper T cells, which play a crucial role in the immune response by coordinating the actions of other immune cells. By recognizing and binding to specific antigens, CD4 helps activate and regulate the immune system.Rate this question:
- 12.
T cells need 2 signals for activation.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Signal 1 occurs when the T cell receptor is engaged by the appropriate MHC bound antigen and the co-receptors CD4 and CD8 bind to MHC molecules.
Signal 2 occurs when CD28 on the T cell interacts with co-stimulatory molecules (CD80 and CD86) expressed on antigen presenting cells.Rate this question:
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- 13.
Under the influence of IL-2, T cells proliferate, generating a large number of antigen-specific lymphocytes. They differentiate into _ _ _ _ _ _ _ _ cells and _ _ _ _ _ _ cells. (separate answers with a comma)
Correct Answer
effector, memoryExplanation
Under the influence of IL-2, T cells proliferate, generating a large number of antigen-specific lymphocytes. These lymphocytes differentiate into effector cells and memory cells. Effector cells are responsible for the immediate immune response, while memory cells are long-lived cells that provide long-term immunity and can quickly respond to future infections by the same antigen.Rate this question:
- 14.
T-helper -1 cells are CD4+ T cells that secrete which cytokines? (2 most important)
- A.
IL-1
- B.
IL-2
- C.
IL-4
- D.
IL-5
- E.
TNF
- F.
IFN-Îł
Correct Answer(s)
B. IL-2
F. IFN-ÎłExplanation
IFN-Îł facilitates delayed hypersensitivity, macrophage activation and synthesis of opsonizing and complement fixing antibodies.
IL-2 stimulates proliferation and differentiation of T cellsRate this question:
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- 15.
T-helper -2 cells are CD4+ T cells that secrete which cytokines? (3 most important)
- A.
IL-1
- B.
IL-2
- C.
IL-4
- D.
IL-5
- E.
IL-13
- F.
IFN-Îł
- G.
TNF
Correct Answer(s)
C. IL-4
D. IL-5
E. IL-13Explanation
IL-4 and IL-13 aids the synthesis of IgE (and other immunoglobulins to a lesser extent)
IL-5 activates eosinophilsRate this question:
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- 16.
CD8+ T cells act mainly as _ _ _ _ _ _ _ _ _ cells.
Correct Answer(s)
cytotoxicExplanation
CD8+ T cells act mainly as cytotoxic cells. Cytotoxic cells are a type of immune cells that are responsible for killing infected or abnormal cells in the body. CD8+ T cells recognize specific antigens on the surface of these cells and release toxic substances to destroy them. This process helps to eliminate pathogens, such as viruses or cancer cells, and maintain the overall health of the body.Rate this question:
- 17.
In the spleen, B lymphocytes are found in the _ _ _ _ _ _ _ _ _, in the lymph nodes they are found in the _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. At both sites they aggregate to form lyphoid follicles. (separate answers with a comma)
Correct Answer(s)
white pulp, superficial cortexExplanation
In the spleen, B lymphocytes are found in the white pulp, while in the lymph nodes they are found in the superficial cortex. At both sites, they aggregate to form lymphoid follicles.Rate this question:
- 18.
Where do plasma cells mainly reside? (3)
- A.
Bone marrow
- B.
Glandular tissue
- C.
Mucosal tissue
- D.
Lymphoid tissue
- E.
Neural tissue
- F.
Circulating blood
Correct Answer(s)
A. Bone marrow
C. Mucosal tissue
D. Lymphoid tissueExplanation
Plasma cells mainly reside in three locations: bone marrow, mucosal tissue, and lymphoid tissue. These locations provide the necessary environment for the survival and function of plasma cells. Bone marrow is the primary site for plasma cell production, where they are generated from B cells. Mucosal tissue, such as the lining of the respiratory and gastrointestinal tracts, also contains plasma cells, which play a role in immune defense at these sites. Lymphoid tissue, including lymph nodes and spleen, is another important location for plasma cells, where they contribute to the immune response by producing antibodies.Rate this question:
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- 19.
CD56 and which other CD molecule are the 2 cell surface molecules generally used to identify natural killer cells?
- A.
CD3
- B.
CD4
- C.
CD8
- D.
CD16
- E.
CD40
- F.
CD56
Correct Answer
D. CD16Explanation
NK cells are CD3 negative. CD40 is the molecule that CD4+ T cells use to assist in B cell responses.Rate this question:
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- 20.
X-linked hyper-IgM syndrome is an immunodeficiency disease cause by a mutation in the gene for which ligand? _ _ _ _
Correct Answer
CD40Explanation
Because CD40 interactions are involved in change of IgM production to IgG production.Rate this question:
- 21.
Expression of class I MHC molecules _ _ _ _ _ _ _ s killing by natural killer cells.
Correct Answer
inhibitsExplanation
All normal nucleated cells express class I MHC. Viral infection and neoplasm cause a reduction of class I MHC thereby losing this inhibtion and promoting NKC killing.Rate this question:
- 22.
What is type I hypersensitivity is also known as?
- A.
Cell-mediated hypersensitivity
- B.
Immediate hypersensitivity
- C.
Antibody mediated hypersensitivity
- D.
Immune complex hypersensitivity
Correct Answer
B. Immediate hypersensitivityExplanation
Prototype disorder = AnaphylaxisRate this question:
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- 23.
What is type II hypersensitivity is also known as?
- A.
Cell-mediated hypersensitivity
- B.
Immediate hypersensitivity
- C.
Antibody mediated hypersensitivity
- D.
Immune complex hypersensitivity
Correct Answer
C. Antibody mediated hypersensitivityExplanation
Prototype disorder = Goodpasture SyndromeRate this question:
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- 24.
What is type III hypersensitivity is also known as?
- A.
Cell-mediated hypersensitivity
- B.
Immediate hypersensitivity
- C.
Antibody-mediated hypersensitivity
- D.
Immune complex hypersensitivity
Correct Answer
D. Immune complex hypersensitivityExplanation
Prototype disorder = SLERate this question:
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- 25.
What is type IV hypersensitivity is also known as?
- A.
Cell-mediated hypersensitivity
- B.
Immediate hypersensitivity
- C.
Antibody-mediated hypersensitivity
- D.
Immune complex hypersensitivity
Correct Answer
A. Cell-mediated hypersensitivityExplanation
Prototype disorders = transplant rejection, TB, contact dermatitis.Rate this question:
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- 26.
What are the 4 major components of innate immunity?
- A.
Epithelium, natural killer cells, phagocytes, plasma proteins
- B.
Erythrocytes, natural killer cells, macrophages, plasma proteins
- C.
Erythrocytes, natural killer cells, neutrophils, complement system
- D.
Epithelium, natural killer cells, lymphocytes, complement system
Correct Answer
A. Epithelium, natural killer cells, phagocytes, plasma proteinsExplanation
All require no previous sensitisation:
Epithelium acts as a barrier
Natural killer cells will kill cells that do not express enough MHC class 1 molecules
The main phagocytes are neutrophils and macrophages
Proteins of the complement system are the main plasma proteins most heavily involved in innate immunityRate this question:
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- 27.
Which class of MHC molecules does CD4 bind to?
- A.
MHC class I
- B.
MHC class II
- C.
MHC class III
Correct Answer
B. MHC class IIExplanation
CD4 molecules bind to MHC class II molecules. MHC class II molecules are found on the surface of antigen-presenting cells, such as dendritic cells, macrophages, and B cells. They present antigens to CD4+ T cells, which play a crucial role in immune responses. CD4 molecules bind to the MHC class II molecule in a specific manner, allowing for the activation of CD4+ T cells and the initiation of an immune response.Rate this question:
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- 28.
Which class of MHC molecules does CD8 bind to?
- A.
MHC class I
- B.
MHC class II
- C.
MHC class III
Correct Answer
A. MHC class IExplanation
CD8 binds to MHC class I molecules. MHC class I molecules are found on the surface of all nucleated cells and present antigens to CD8+ T cells. These antigens are usually derived from intracellular pathogens or proteins produced within the cell. CD8 binds to the MHC class I molecule in order to recognize and respond to these antigens, leading to the activation of cytotoxic T cells and the elimination of infected or abnormal cells. MHC class II molecules, on the other hand, present antigens to CD4+ T cells. MHC class III molecules are not involved in antigen presentation.Rate this question:
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- 29.
Which T cell subset is involved in facilitating delayed hypersensitivity, macrophage activation and synthesis of opsonizing and complement fixing antibodies due to the actions of IFN-γ?
- A.
T-helper-1
- B.
T-helper-2
- C.
T-helper-3
Correct Answer
A. T-helper-1Explanation
T-helper-1 (Th1) cells are involved in facilitating delayed hypersensitivity, macrophage activation, and synthesis of opsonizing and complement-fixing antibodies due to the actions of IFN-Îł. Th1 cells produce IFN-Îł, which activates macrophages and enhances their ability to kill intracellular pathogens. IFN-Îł also stimulates B cells to produce opsonizing antibodies and promotes the activation of the complement system. Th1 cells are primarily involved in cell-mediated immune responses and play a crucial role in defense against intracellular pathogens.Rate this question:
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- 30.
Which T cell subset is involved in synthesis of IgE and activation of eosinophils?
- A.
T-helper-1
- B.
T-helper-2
- C.
T-helper-3
Correct Answer
B. T-helper-2Explanation
T-helper-2 cells are involved in the synthesis of IgE and activation of eosinophils. These cells play a crucial role in allergic responses and asthma. T-helper-2 cells produce cytokines such as IL-4, IL-5, and IL-13, which stimulate B cells to produce IgE antibodies. IgE antibodies then bind to mast cells and basophils, triggering the release of inflammatory mediators. T-helper-2 cells also promote the recruitment and activation of eosinophils, which are involved in the immune response against parasites and contribute to allergic inflammation. Therefore, T-helper-2 cells are the correct answer in this context.Rate this question:
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- 31.
IL-1, IL-6, type 1 interferons and TNF are cytokines that mainly mediate adaptive immunity.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
IL-1, IL-6 and TNF are cytokines that mainly mediate INNATE immunity.
Interferons protect against viral infections.
IL-1 and TNF promote leukocyte recruitment and acute inflammatory responses.Rate this question:
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- 32.
Cytokines have autocrine and paracrine actions, but not endocrine actions.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
They can act in all 3 ways.Rate this question:
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- 33.
The principal physiologic function of the cell surface histocompatibility molecules is to bind peptide fragments of foreign proteins for presentation to antigen specific _ _ _ _ _ _.
Correct Answer
T cellsExplanation
The principal physiologic function of the cell surface histocompatibility molecules is to bind peptide fragments of foreign proteins for presentation to T cells.Rate this question:
- 34.
T cells can only recognise membrane bound antigens.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
T cells can only recognize antigens that are presented on the surface of cells, which are referred to as membrane-bound antigens. This recognition occurs through the interaction of the T cell receptor (TCR) with the antigen-presenting molecule called major histocompatibility complex (MHC). Therefore, the statement that T cells can only recognize membrane-bound antigens is true.Rate this question:
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- 35.
Which of the following diseases are associated with HLA-B27? (3)
- A.
Ankylosing Spondylitis
- B.
Type 1 Diabetes
- C.
Postgonococcal arthritis
- D.
Rheumatoid arthritis
- E.
Osteoarthritis
- F.
Acute anterior uveitis
- G.
Chronic active hepatitis
- H.
Primary Sjogren syndrome
Correct Answer(s)
A. Ankylosing Spondylitis
C. Postgonococcal arthritis
F. Acute anterior uveitisExplanation
Ankylosing Spondylitis, Postgonococcal arthritis, and Acute anterior uveitis are associated with HLA-B27. HLA-B27 is a genetic marker that is strongly associated with these diseases. Ankylosing Spondylitis is a chronic inflammatory disease that primarily affects the spine and sacroiliac joints. Postgonococcal arthritis is a type of arthritis that occurs as a complication of a gonorrhea infection. Acute anterior uveitis is inflammation of the front part of the eye. These diseases have been found to have a higher prevalence in individuals who have the HLA-B27 gene.Rate this question:
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- 36.
Which of the following diseases are associated with HLA-DR3? (3)
- A.
Type 1 Diabetes
- B.
Type 2 Diabetes
- C.
Osteoarthritis arthritis
- D.
Rheumatoid arthritis
- E.
Acute hepatitis
- F.
Chronic active hepatitis
- G.
Primary Sjogren syndrome
- H.
Hereditary haemochromatosis
Correct Answer(s)
A. Type 1 Diabetes
F. Chronic active hepatitis
G. Primary Sjogren syndromeExplanation
Rheumatoid arthritis is associated with HLA-DR4.
Type 1 diabetes is associated with HLA-DR4 as well as HLA-DR3.
Hereditary haemochromatosis is associated with HLA-ARate this question:
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- 37.
Diseases that show association with the HLA locus can be broadly grouped into 3 categories. Which of the following is NOT one of these categories?
- A.
Neoplastic predisposition
- B.
Inflammatory disease
- C.
Inherited errors of metabolism
- D.
Autoimmune disorders
Correct Answer
A. Neoplastic predispositionExplanation
Neoplastic predisposition is not one of the categories of diseases that show association with the HLA locus. The HLA locus is primarily associated with the immune system and plays a role in autoimmune disorders, inflammatory diseases, and inherited errors of metabolism. Neoplastic predisposition refers to an increased risk of developing cancer due to genetic factors unrelated to the HLA locus.Rate this question:
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- 38.
Vascular dilation, oedema, smooth muscle contraction and mucous production are the pathologic lesions seen in which type of hypersensitivity reaction?
- A.
Type I
- B.
Type II
- C.
Type III
- D.
Type IV
Correct Answer
A. Type IExplanation
Mast cells are central to the development of immediate hypersensitivityRate this question:
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- 39.
Cell lysis and inflammation are the pathologic lesions seen in which type of hypersensitivity reaction?
- A.
Type I
- B.
Type II
- C.
Type III
- D.
Type IV
Correct Answer
B. Type IIExplanation
In Type II hypersensitivity reactions, cell lysis and inflammation are the pathologic lesions observed. This type of hypersensitivity reaction involves the binding of antibodies to antigens on the surface of cells or tissues, leading to the activation of the complement system and subsequent destruction of the affected cells. This process triggers an inflammatory response, resulting in tissue damage and inflammation.Rate this question:
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- 40.
Necrotising vasculitis and inflammation are the pathologic lesions seen in which type of hypersensitivity reaction?
- A.
Type I
- B.
Type II
- C.
Type III
- D.
Type IV
Correct Answer
C. Type IIIExplanation
Necrotising vasculitis and inflammation are the pathologic lesions seen in Type III hypersensitivity reactions. In this type of reaction, immune complexes formed by the binding of antibodies to antigens are deposited in various tissues, leading to an inflammatory response. The immune complexes can activate complement and attract neutrophils, causing tissue damage and inflammation. This type of hypersensitivity reaction is associated with diseases such as systemic lupus erythematosus and rheumatoid arthritis.Rate this question:
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- 41.
Perivascular cellular infiltrates, oedema, cell duestruction and granuloma formation are pathologic lesions seen in which type of hypersensitivity reaction?
- A.
Type I
- B.
Type II
- C.
Type III
- D.
Type IV
Correct Answer
D. Type IVExplanation
Perivascular cellular infiltrates, edema, cell destruction, and granuloma formation are characteristic pathological lesions seen in Type IV hypersensitivity reactions. Type IV hypersensitivity reactions, also known as delayed-type hypersensitivity reactions, are mediated by T cells and occur 24-72 hours after exposure to an antigen. These reactions are typically associated with chronic inflammation and tissue damage. Examples of Type IV hypersensitivity reactions include contact dermatitis, tuberculin reaction, and granulomatous diseases such as sarcoidosis.Rate this question:
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- 42.
Most immediate hypersensitivity reactions are mediated by which type of immunoglobulin?
- A.
IgA
- B.
IgD
- C.
IgE
- D.
IgG
- E.
IgM
Correct Answer
C. IgEExplanation
The differentiation of naive B cells into IgE secreting B cells is dependent on the activity of T-helper-2 cells.Rate this question:
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- 43.
_ _ _ _ _ refers to the predisposition to develop localised immediate hypersensitivity reactions to a cariety of inhales and ingested allergens?
Correct Answer
atopyExplanation
Atopy refers to the predisposition to develop localized immediate hypersensitivity reactions to a variety of inhaled and ingested allergens. This means that individuals with atopy are more likely to have allergic reactions when exposed to certain substances, such as pollen, dust mites, or certain foods. These reactions can manifest as symptoms like sneezing, itching, and difficulty breathing. Atopy is thought to have a genetic component and can be influenced by environmental factors.Rate this question:
- 44.
Chronic granulomatous disease is characterised by recurrent life-threatening infections with bacteria and fungi, and granuloma formation. It can be x-linked or autosomal dominant or recessive. It is caused by multiple molecular defects in phox genes of _ _ _ _ _ oxidase.
Correct Answer
NADPHExplanation
Chronic granulomatous disease is a condition characterized by recurrent infections and the formation of granulomas. It can be inherited in different ways, such as being X-linked or autosomal dominant or recessive. The disease is caused by multiple molecular defects in phox genes of NADPH oxidase. NADPH is an important molecule involved in the respiratory burst, which is a process used by immune cells to kill bacteria and fungi. Defects in the phox genes prevent the production of functional NADPH oxidase, leading to impaired immune function and increased susceptibility to infections.Rate this question:
- 45.
In X-linked agammaglobulinaemia, there is a failure of B cells to mature beyond which stage of development?
- A.
Stem cell
- B.
Pro-B cell
- C.
Pre-B cell
- D.
Immature B cell
- E.
Mature B cell
Correct Answer
C. Pre-B cellExplanation
AKA Bruton’s agammaglobulinaemia
Absence of gammaglobulins in blood
Failure to mature beyond pre-B cell stage in the bone marrow
Mutations or deletions in gene encoding enzyme tyrosine kinase (Btk)
Low or undectable Ig, reduced or absent B cells in lymphoid tissues, no germinal centres in lymph nodes
T cells maturation, numbers and functions: normal
Autoimmunity in 20%
Monthly IvIg reduces infectious complicationsRate this question:
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- 46.
Which is the most common type of selective immunoglobulin deficiency?
- A.
IgA
- B.
IgD
- C.
IgE
- D.
IgG
- E.
IgM
Correct Answer
A. IgAExplanation
Usually sporadic
Phenotypically normal; some may have respiratory infections and diarrhoea, or is expressed if there is a second immunodeficiency.
Risk of anti-IgA sensitisation and anaphylactoid reactions following exposure to IgA containing blood productsRate this question:
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- 47.
Type II hypersensitivity reactions can result in phagocytosis, lysis, inflammation or dysregulated function (impaired or excessively stimulated) of of target cells.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Anti-body mediated, mostly by binding of Fc fragments. Complement is also heavily involved in some reactions.Rate this question:
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- 48.
What 3 viral enzymes are contained in the HIV virion?
- A.
Catalase
- B.
Helicase
- C.
Integrase
- D.
Phospholipase
- E.
Protease
- F.
Reverse transcriptase
Correct Answer(s)
C. Integrase
E. Protease
F. Reverse transcriptaseExplanation
The three viral enzymes contained in the HIV virion are Integrase, Protease, and Reverse transcriptase. Integrase is responsible for integrating the viral DNA into the host cell's DNA. Protease plays a crucial role in the maturation of the virus by cleaving the viral polyprotein into individual functional proteins. Reverse transcriptase is involved in the replication process of the virus, converting the viral RNA into DNA. These enzymes are essential for the replication and survival of the HIV virus within the host.Rate this question:
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- 49.
Which genes (that code for viral proteins) are contained in the HIV-1 viral genome? (3)
- A.
Env
- B.
Gac
- C.
Myc
- D.
Phox
- E.
Pol
- F.
Ras
Correct Answer(s)
A. Env
B. Gac
E. PolExplanation
The correct answer is env, gac, and pol. These genes code for viral proteins that are contained in the HIV-1 viral genome. The env gene codes for the envelope glycoprotein, which is responsible for viral entry into host cells. The gac gene codes for the group-specific antigen, which is a viral structural protein. The pol gene codes for the viral enzymes, such as reverse transcriptase, protease, and integrase, that are essential for viral replication.Rate this question:
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- 50.
The identification of which capsid protein in HIV can be used for diagnosis before HIV antibodies have been produced?
- A.
CD4
- B.
Gp120
- C.
P24
- D.
CCR5
Correct Answer
C. P24Explanation
The p24 capsid protein in HIV can be used for diagnosis before HIV antibodies have been produced. This protein is a component of the viral capsid and is detectable in the blood during the early stages of HIV infection, even before antibodies are produced. Therefore, testing for the presence of p24 protein can help in early diagnosis of HIV infection.Rate this question:
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