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Question 1
Incorrect
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Question 2
Incorrect
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The following are all examples of type IV hypersensitivity EXCEPT for:
Your Answer:
Correct Answer: Extrinsic allergic alveolitis
Explanation:Examples of type IV reactions includes: Contact dermatitis Hashimoto’s thyroiditis Primary biliary cholangitis Tuberculin skin test (Mantoux test) Chronic transplant rejection Granulomatous inflammation (e.g. sarcoidosis, Crohn’s disease)
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This question is part of the following fields:
- Immunology
- Pathology
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Question 3
Incorrect
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A 43 year old lady suffering with idiopathic thrombocytopenic purpura has a splenectomy. She is advised to get the Pneumococcal vaccine booster every 5 - 10 years as Streptococcus pneumoniae has which of the following properties that make her prone to infection to this organism?
Your Answer:
Correct Answer: It is encapsulated
Explanation:There is a lifelong susceptibility to increased risk of infection from a variety of organisms in patients with hyposplenism, especially in children under 5 years and those with sickle cell anaemia. Patients are most susceptible is to the encapsulated bacteria Streptococcus pneumoniae, Haemophilus influenzae type B and Neisseria meningitidis. Streptococcus pneumoniae is particular concerning as it can cause rapid and fulminant disease, which can be fatal. Malaria and animal bites that become infected also tend to be more severe.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 4
Incorrect
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Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer:
Correct Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk). IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion. IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 5
Incorrect
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The process whereby bacterial products interact with plasma factors and cells to produce agents that attract neutrophils to an infected area is called:
Your Answer:
Correct Answer: Chemotaxis
Explanation:During an inflammatory process many cytokines are produced that act as chemokines to attract neutrophils to the site of inflammation. These include bacterial products, IL-8, C5a and LTB4.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 6
Incorrect
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Question 7
Incorrect
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What is the function of the acute phase protein, C-reactive protein?
Your Answer:
Correct 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
- Physiology
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Question 8
Incorrect
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Complement system help dispose waste products after which natural process?
Your Answer:
Correct 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
- Physiology
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Question 9
Incorrect
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Type 2 hypersensitivity is mediated by:
Your Answer:
Correct Answer: IgG, IgM & complement
Explanation:In type II hypersensitivity the antibodies, IgG and IgM bind to antigens to form complexes that activate the classical pathway of complement to eliminate cells presenting foreign antigens.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 10
Incorrect
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Tumour necrosis factor is a cytokine. What is its major function?
Your Answer:
Correct 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
- Physiology
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Question 11
Incorrect
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Question 12
Incorrect
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What is the name of the area that indicates the site of active B lymphocyte proliferation?
Your Answer:
Correct 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
- Physiology
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Question 13
Incorrect
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A 42 year old women presents with end stage renal failure and is prepared to receive a kidney from her husband. HLA testing showed that they are not a 100% match and she is given immunosuppressant therapy for this. Three months later when her renal function tests were performed she showed signs of deteriorating renal function, with decreased renal output, proteinuria of +++ and RBCs in the urine. She was given antilymphocyte globulins and her condition reversed. What type of graft did this patient receive?
Your Answer:
Correct Answer: Allograft
Explanation:Allograft describes a graft between two of the same species. As the donor and the recipients are history-incompatible, rejection of the graft is common and is controlled by immunosuppressive drug therapy. Isograft and syngraft are synonymous and referred to a graft transferred between genetically identical individuals e.g. identical twins. In this case rejection is rare as they are history-compatible. Autograft refers to transfer of one part of the body to another location. Xenograft is transfer of tissue from another species e.g. pig to human in valve replacement surgeries and rejection is very high.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 14
Incorrect
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The following are all examples of type I hypersensitivity EXCEPT for:
Your Answer:
Correct Answer: Contact dermatitis
Explanation:Examples of type I reactions include: Allergic rhinitis Allergic conjunctivitis Allergic asthma Systemic anaphylaxis Angioedema Urticaria Penicillin allergy
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This question is part of the following fields:
- Immunology
- Pathology
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Question 15
Incorrect
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Regarding T helper cells, which of the following statements is CORRECT:
Your Answer:
Correct Answer: They form the vast majority (about 75%) of the total circulating T-cell population.
Explanation:CD4+ T-cells (Helper T cells)Recognise antigen only in association with HLA class II molecules (found on antigen presenting cells (APCs) e.g. dendritic cells, B-cells; present exogenous antigens that have been phagocytosed/endocytosed into intracellular vesicles)Form most of the circulating T-cell population (about 75%)Secrete cytokines (e.g. IFN-gamma) which are required for recruitment and activation of other immune cells such as macrophages, T cytotoxic cells and NK cells and for the activation of and production of immunoglobulin from B-cells
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This question is part of the following fields:
- Immunology
- Pathology
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Question 16
Incorrect
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Which of the following acute phase reactants increases the most dramatically in the first hour following injury?
Your Answer:
Correct 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
- Physiology
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Question 17
Incorrect
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Where does control of self-reactive T cells (self-tolerance) initially occur?
Your Answer:
Correct 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
- Physiology
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Question 18
Incorrect
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What is the function of cytotoxic T cells?
Your Answer:
Correct 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
- Physiology
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Question 19
Incorrect
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Question 20
Incorrect
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The most important Complement protein for antigen opsonization is:
Your Answer:
Correct Answer: C3b
Explanation:Phagocytosis is largely responsible for depletion of cells coated with antibodies. Cells opsonized by IgG antibodies are recognized by phagocyte Fc receptors, which are specific for the Fc portions of some IgG subclasses. In addition, when IgM or IgG antibodies are deposited on the surfaces of cells, they may activate the complement system by the classical pathway. Complement activation generates by-products, mainly C3b and C4b, which are deposited on the surfaces of the cells and recognized by phagocytes that express receptors for these proteins. The net result is phagocytosis of the opsonized cells and their destruction.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 21
Incorrect
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In both innate and humoral immunity, receptors involved recognize:
Your Answer:
Correct 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
- Physiology
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Question 22
Incorrect
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Cells mediating innate immunity include:
Your Answer:
Correct 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
- Physiology
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Question 23
Incorrect
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A 30 year old lawyer presented with a history of pleural effusions, pericarditis, arthralgia without joint deformity and episodes of myalgia for the past 12 months. Blood tests reveal a normocytic anaemia. Which of the following tests should be performed to investigate this condition further?
Your Answer:
Correct Answer: Antinuclear antibody test
Explanation:These non specific findings are suggestive of autoimmune disease. Antinuclear antibody (ANA) is the first test that should be performed when autoimmune diseases are suspected and later on more specific tests should be performed. This tests aids in the diagnosis of SLE, scleroderma, Sjogren’s syndrome, Raynaud’s disease, juvenile chronic arthritis, rheumatoid arthritis and antiphospholipid antibody syndrome etc. To confirm the disease a history, physical examination along with specific tests are required. CPK is more specific for acute conditions. ESR is a non specific test for inflammation.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 24
Incorrect
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Which of the following statements about neutrophils is TRUE:
Your Answer:
Correct Answer: Neutrophils are typically the first immune cell to arrive to a site of injury.
Explanation:Neutrophils are the most numerous peripheral blood leukocytes, accounting for 50-70 percent of all circulating white cells. Neutrophils have a compact nucleus with two to five lobes and a pale cytoplasm with an irregular shape containing numerous fine pink-blue or grey-blue granules. The granules are classified as primary, which emerges during the promyelocyte stage, and secondary, which develop at the myelocyte stage and predominate in the mature nucleus. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 25
Incorrect
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Eosinophils provide immunity against
Your Answer:
Correct 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
- Physiology
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Question 26
Incorrect
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Humoral immunity is a major defence against:
Your Answer:
Correct 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
- Physiology
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Question 27
Incorrect
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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:
Correct 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
- Physiology
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Question 28
Incorrect
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Which is the primary lymphoid organ?
Your Answer:
Correct 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
- Physiology
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Question 29
Incorrect
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A 28 years old women presents with a history of chronic cough with fever for the past 2 months. A chest x ray revealed a diffuse bilateral reticulonodular pattern. A transbronchial biopsy was performed and histological examination showed focal areas of inflammation with epithelioid macrophages, Langhans cells and lymphocytes. Which of the immune reaction is responsible for this?
Your Answer:
Correct Answer: Type IV hypersensitivity
Explanation:A reactivated tuberculosis with granuloma formation is characteristic of type IV reaction. It is also called a delayed type of hypersensitivity reaction and takes around 2-8 days to deliver. It is a cell mediated response with the involvement of CD8 and CD4 cells and the release of IL-1 from macrophages that further activate these CD cells.Granulomatous reactions are mostly cell-mediated. Type I reactions are allergic and anaphylactic reactions and type II are complement-mediated immune reactions.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 30
Incorrect
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Mast cells play a significant part in which of the following?
Your Answer:
Correct Answer: Allergic disease
Explanation:Mast cells play a central role in the response to allergen challenges. The activation of mast cells results in both an early and a delayed phase of inflammation. Mast cells have been implicated in both physiologic and pathogenic processes. Mast cells are important in defence against some bacteria and viruses and contribute to defence against parasites. They are key effector cells in both innate and acquired immunity and are capable of inducing and amplifying both types of responses. Specifically, mast cells are capable of detecting microbial products through surface pattern recognition receptors, and they are involved in the recruitment of other leukocytes, containment of bacterial infections, and tissue repair.
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This question is part of the following fields:
- Immunology
- Pathology
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