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Question 1
Correct
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Cells mediating innate immunity include:
Your Answer: Natural killer cells
Explanation:Natural killer cells have features of both innate and adaptive immunity. They play an important part in defence against tumours and viruses. They are non specific and do not generate immunological memory
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This question is part of the following fields:
- Immunology
- Medicine
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Question 2
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Neutrophils are key components of the innate immune system. They contain numerous primary and secondary granules involved in killing and digesting microorganisms. With regard to defensins, they are:
Your Answer: Naturally occurring cysteine-rich antibacterial and antifungal polypeptides
Explanation:Cationic antimicrobial peptides, including defensins, cathelicidins, and thrombocidins, provide important initial defences against invading microbes. These peptides bind the bacterial membrane and form pores, killing the bacterium by hypo-osmotic lysis.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 3
Correct
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Eosinophils provide immunity against
Your Answer: Multi cellular parasites
Explanation:Eosinophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 4
Correct
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Complement system help dispose waste products after which natural process?
Your Answer: Apoptosis
Explanation:The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism or apoptosis. It is part of the innate immune system.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 5
Correct
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What is the name of the area that indicates the site of active B lymphocyte proliferation?
Your Answer: Germinal centre
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 6
Correct
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Question 7
Correct
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The predominant site in the lymph node where T lymphocytes are found is:
Your Answer: Paracortex
Explanation:Paracortex is found between the cortex and the medulla and it is composed of a non-nodular type of arrangement that is mostly made up of T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 8
Correct
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The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Cortex
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate. The cortex of the lymph node predominately consists of B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 9
Correct
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Which of the following features do mast cells and basophils have in common:
Your Answer: Are essential for immediate type-hypersensitivity reactions
Explanation:Anaphylaxis is a severe immediate allergic reaction of rapid onset affecting many body systems. It is due to the release of inflammatory mediators and cytokines from mast cells and basophils. Basophils are the least common of the granulocytes, representing about 0.5 to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They can perform phagocytosis (cell eating), produce histamine and serotonin that induce inflammation, and heparin that prevents blood clotting. Mast cells are similar in appearance and function. Both cell types store histamine, a chemical that is secreted by the cells when stimulated.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 10
Correct
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Which immunological cells are predominant in the lymph node (almost 98 % residence)?
Your Answer: Lymphocytes
Explanation:Lymph nodes are a lymphoid organ mostly consisting of lymphocytes: B cells in the cortex from where they mature and proliferate and T cells in the paracortex. The medulla is also composed of lymphocytes and macrophages.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 11
Correct
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The collection of genes that are termed the major histocompatibility complex (MHC) are found on:
Your Answer: Short arm of chromosome 6
Explanation:Histocompatibility, or tissue compatibility, is the property of having the same, or sufficiently similar, alleles of a set of genes called human leukocyte antigens (HLA). HLA is the human form of the major histocompatibility complex (MHC) genes found in all vertebrates. On a population level there is a great number of different alleles at each HLA locus on the short arm of chromosome 6
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This question is part of the following fields:
- Immunology
- Medicine
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Question 12
Correct
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The immunoglobulin found in the highest concentration in humans is
Your Answer: IgG
Explanation:Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 13
Correct
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Which of the following cells release histamines when they are activated by binding of specific antigens to cell fixed IgE molecules?
Your Answer: Basophils
Explanation:Mast cells and basophils both contain granules of vasoactive histamine in their cytosol. Both of them express IgE receptors on their cell surface and upon binding with a specific antigen they release their cytokines including histamine.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 14
Correct
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Which cells produce the immunoglobulin proteins involved in mediating humoral immunity?
Your Answer: Differentiated forms of B lymphocytes known as plasma cells
Explanation:After the B cells have been activated by a certain antigens, they transform into plasma cells. These plasma cells are responsible for the generation of antibodies (or immunoglobulins Ig) which are also known as regulators of humoral immunity. There are fives classes of Ig: IgA, IgG, IgM, IgE and IgD
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This question is part of the following fields:
- Immunology
- Medicine
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Question 15
Correct
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Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 16
Correct
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Question 17
Correct
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Question 18
Correct
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The only APCs that can activate naive T lymphocytes are:
Your Answer: Dendric cells
Explanation:Only professional antigen-presenting cells (macrophages, B lymphocytes, and dendritic cells) are able to activate a resting helper T-cell when the matching antigen is presented. However, macrophages and B cells can only activate memory T cells whereas dendritic cells can activate both memory and naive T cells, and are the most potent of all the antigen-presenting cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 19
Correct
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What is the function of the acute phase protein, C-reactive protein?
Your Answer: Opsonises bacteria
Explanation:There are various immune reactions that become activated once the barrier between the body and environment has been compromised. There are certain opsonins that bind to the bacteria and facilitate phagocytosis. One of them is the acute phase protein: C protein. others include antibodies and complement.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 20
Correct
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What is the function of cytotoxic T cells?
Your Answer: Kill by inserting perforins and by initiating apoptosis
Explanation:Cytotoxic T cells, once activated, approach the infected cell, insert perforins and release granzymes inducing apoptosis.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 21
Correct
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Amongst the following cells, which is responsible for the secretion of defensins?
Your Answer: Neutrophils
Explanation:Eosinophils are phagocytic and they are directed against helminths. Basophils are involved in allergic reactions and contain histamine and vasoactive granules in their cytoplasm. Mast cells are similar to basophils. Monocytes differentiate into macrophages in the tissue, secret interleukins and are phagocytic. Neutrophils are phagocytic but are also responsible for secreting defensins.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 22
Correct
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Question 23
Correct
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Humoral immunity is a major defence against:
Your Answer: Viral infections
Explanation:Humoral immunity is provided by the neutralizing and non-neutralizing antibodies that are formed from the B lymphocytes. This form of immunity is most important in viral infection. Non-neutralizing antibodies increases phagocytosis of the infected cell and inhibit the ability of the virus to replicate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 24
Correct
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Question 25
Correct
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Which of the following cells are attracted to the surface of endothelium by selectins?
Your Answer: Neutrophils
Explanation:Selectins are expressed on the surface of the endothelium. P selectins are released from weibel-palade bodies and E selectins are induced by cytokines (TNF and IL-1). They bind to receptors on the neutrophils called saiyl lewis X.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 26
Correct
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In both innate and humoral immunity, receptors involved recognize:
Your Answer: The shape of the antigen
Explanation:Antigen receptors recognize the shape of the antigen. They identify specific epitopes and are found on T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 27
Correct
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Where does control of self-reactive T cells (self-tolerance) initially occur?
Your Answer: Thymus
Explanation:The thymus provides an inductive environment for development of T cells from hematopoietic progenitor cells. In addition, thymic stromal cells allow for the selection of a functional and self-tolerant T cell repertoire. Therefore, one of the most important roles of the thymus is the induction of central tolerance.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 28
Correct
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Neutrophils are attracted to an infected area by:
Your Answer: Chemokines
Explanation:The major role of chemokines is to act as a chemoattractant to guide the migration of cells like neutrophils to the site of infection.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 29
Correct
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Which of the following acute phase reactants increases the most dramatically in the first hour following injury?
Your Answer: C-reactive protein
Explanation:Measurement of acute-phase proteins, especially C-reactive protein, is a useful marker of inflammation. It correlates with the erythrocyte sedimentation rate (ESR), however not always directly. This is due to the ESR being largely dependent on elevation of fibrinogen, an acute phase reactant with a half-life of approximately one week. This protein will therefore remain higher for longer despite removal of the inflammatory stimuli. In contrast, C-reactive protein (with a half-life of 6-8 hours) rises rapidly and can quickly return to within the normal range if treatment is employed.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 30
Correct
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Which is the primary lymphoid organ?
Your Answer: Thymus
Explanation:Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.
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This question is part of the following fields:
- Immunology
- Medicine
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