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Question 1
Incorrect
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Neutrophils are attracted to an infected area by:
Your Answer: Cytokines
Correct 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
- Physiology
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Question 2
Correct
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In all of the following conditions, lymphocytosis typically occurs except for:
Your Answer: Corticosteroid therapy
Explanation:In infants and young children, lymphocytosis often occurs in response to infections that would normally produce a neutrophil reaction in adults. Lymphocytosis occurs in: 1. Viral infections (e.g. infectious mononucleosis, HIV, rubella, mumps, viral hepatitis, cytomegalovirus, herpes simplex or zoster) 2. Bacterial infections (e.g. pertussis, tuberculosis, toxoplasmosis, syphilis) 3. Chronic lymphoid leukaemias 4. Acute lymphoblastic leukaemias 5. Non-Hodgkin lymphoma 6. Thyrotoxicosis
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This question is part of the following fields:
- Immunology
- Pathology
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Question 3
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
- Physiology
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Question 4
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: Syngraft
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 5
Incorrect
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The collection of genes that are termed the major histocompatibility complex (MHC) are found on:
Your Answer: On the human leukocyte antigens
Correct 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
- Physiology
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Question 6
Incorrect
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Which of the following does NOT typically cause a neutrophil leucocytosis:
Your Answer: Acute appendicitis
Correct Answer: Glandular fever
Explanation:Causes of neutrophil leucocytosis: Bacterial infection Inflammation and tissue necrosis (e.g. cardiac infarct, trauma, vasculitis, myositis) Metabolic disorders (e.g. uraemia, acidosis, eclampsia, gout) Pregnancy Acute haemorrhage or haemolysis Neoplasms of all types Drugs (e.g. corticosteroid therapy, lithium, tetracyclines) Asplenia Myeloproliferative disorders (e.g. CML, essential thrombocythaemia, polycythaemia vera, myelofibrosis) Rare inherited disorders
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This question is part of the following fields:
- Immunology
- Pathology
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Question 7
Incorrect
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Which of the following features do mast cells and basophils have in common:
Your Answer: Are essential for delayed type-hypersensitivity reactions
Correct 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
- Physiology
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Question 8
Incorrect
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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: Eosinophils
Correct 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
- Physiology
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Question 9
Incorrect
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A 40 year old woman, who is under anaesthesia for an elective procedure, received an antibiotic injection. She immediately developed a rash and her airway constricted raising the airway pressure. Which mechanism is responsible for this reaction?
Your Answer: Type IV hypersensitivity
Correct Answer: Type I hypersensitivity
Explanation:Type I hypersensitivity reaction is an immediate reaction that occurs due to binding of the antigen with antibodies attached to mast cells in a previously sensitized person. It has an immediate phase, which is characterised by vasodilation, leakage of plasma, smooth muscle spasm, or glandular secretions. This manifests in about 5-30 min and usually resolves within 60 mins. The delayed phase follows after 24 hours and can persist up to several days. It is due to infiltration of eosinophils, neutrophils, basophils and CD4+ cells and leads to tissue destruction. The nature of the reaction varies according to the site. It can take the form of skin allergy, hives, allergic rhinitis, conjunctivitis, bronchial asthma or food allergy.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 10
Correct
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Eosinophils comprise what percentage of circulating white cells:
Your Answer: 1 - 3%
Explanation:Eosinophils comprise 1 – 3% of circulating white cells. Eosinophils are similar to neutrophils, except that the cytoplasmic granules are coarser and more deeply red staining, and there are rarely more than three nuclear lobes. They are less motile, but longer lived. They enter inflammatory exudates and have a special role in allergic responses, defence against parasites and removal of fibrin formed during inflammation. Thus they play a role in local immunity and tissue repair.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 11
Incorrect
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Question 12
Incorrect
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Amongst the following cells, which is responsible for the secretion of defensins?
Your Answer: Eosinophils
Correct 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
- Physiology
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Question 13
Correct
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Regarding red blood cell group antigens and antibodies, which of the following statements is CORRECT:
Your Answer: Anti-D antibodies are usually IgG.
Explanation:Approximately 400 red blood cell group antigens have been described. The ABO group antigens are unusual in that naturally occurring antibodies occur in the plasma of subjects who lack the corresponding antigen, even if they have not been exposed to that antigen previously. The most important of these natural antibodies are anti-A and anti-B, which are usually IgM. Anti-D antibodies don’t occur naturally, and are therefore immune antibodies that result from previous transfusions or pregnancy. Only IgG antibodies are capable of transplacental passage and the most important immune antibody is the Rh antibody, anti-D.
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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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Which cell type functions as the critical bridge between innate and adaptive immune systems, by activating naïve T lymphocytes?
Your Answer: Mast cells
Correct Answer: Dendritic cells
Explanation:Dendritic cells are antigen presenting cells. They express class II MHC and T cell co-stimulatory molecules. They bind antigens and present them to native T cells and in the process activate the specific T cell against that antigen.
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This question is part of the following fields:
- Immunology
- Physiology
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Question 15
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
- Physiology
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Question 16
Incorrect
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The only APCs that can activate naive T lymphocytes are:
Your Answer: Helper t cells
Correct 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
- Physiology
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Question 17
Incorrect
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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer: Superoxide dismutase forms h2o2
Correct Answer: NADPh oxidase
Explanation:Catalase Degrades H2O2 to H20 and O2, Superoxide Dismutase Forms H2O2, Myeloperoxidase Converts Br/I/Cl to acids
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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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Which of the following statements is correct with regards to natural killer cells?
Your Answer: NK cells target cells that have a high level of HLA Class I molecule expression.
Correct Answer: They are part of the innate immune system.
Explanation:Natural Killer (NK) Cells are lymphocytes in the same family as T and B cells, which come from a common progenitor. They are cytotoxic CD8 positive cells that do not have the T-cell receptor. They are very big cells with cytoplasmic granules and are designed to kill target cells with a low level of expression of HLA class I molecules. Examples include during a viral infection or on a malignant cell. NK cells display several receptors for HLA molecules on their surface, and when HLA is expressed on the target cell, these deliver an inhibitory signal into the NK cell. Absent HLA molecules on the target cell cause this inhibitory signal to get lost and as a result, the NK cell can then kill its target. Also, NK cells display antibody-dependent cell-mediated cytotoxicity, where antibody binds to antigen on the surface of the target cell. The NK cells then bind to the Fc portion of the bound antibody and kill the target cell.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 19
Incorrect
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Which of the following cells are attracted to the surface of endothelium by selectins?
Your Answer: Lymphocytes
Correct 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
- Physiology
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Question 20
Incorrect
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A 42 year old man presents with end stage renal failure and is prepared to receive a kidney from his best friend. HLA testing showed that they are not a 100% match and he is given immunosuppressant therapy for this. Three months later when his renal function is assessed, he showed signs of deteriorating renal function, with decreased renal output, proteinuria of +++ and RBCs in the urine. He was given antilymphocyte globulins and his condition reversed. During the crisis period the patient is likely to be suffering from?
Your Answer: Graft-versus-host disease
Correct Answer: Acute rejection
Explanation:This patients is most likely experiencing an acute rejection. It is a cell mediated attack against the organ that has been transplanted. Antigens are either presented by blood borne cells with in the graft or antigen presenting cells in the body may be presenting class I and class II molecules that have been shed by the graft. Class I will activate CD8 and class II, CD4 cells, both of which will attack the graft. Chronic rejection is a slow process which occurs months to years after the transplant. The exact mechanism is not very well understood but it probably involves a combination of Type III and Type IV hypersensitivity directed against the foreign MHC molecules which look like self-MHC presenting a foreign antigen. Hyperacute Transplant Rejection occurs almost immediately and is often evident while you are still in surgery. It is caused by accidental ABO Blood type mismatching of the donor and recipient which almost never happens anymore. This means the host has preformed antibodies against the donated tissue.
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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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Which immunological cells are predominant in the lymph node (almost 98 % residence)?
Your Answer: Monocytes
Correct 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
- Physiology
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Question 22
Incorrect
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Which of the following is the most abundant immunoglobulin in plasma:
Your Answer: IgE
Correct Answer: IgG
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 23
Incorrect
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In which of the following would you NOT typically see a neutropaenia:
Your Answer: Chemotherapy
Correct Answer: Asplenism
Explanation:Causes of neutropaenia: Drug-induced (e.g. chemotherapy, chloramphenicol, co-trimoxazole, phenytoin, carbamazepine, carbimazole, furosemide, chloroquine, clozapine, some DMARDs) Benign (racial or familial) Cyclical Immune (e.g. SLE, Felty’s syndrome, hypersensitivity and anaphylaxis) Leukaemia Infections (e.g. HIV, hepatitis, fulminant bacterial infection) General Pancytopaenia Hypersplenism, aplastic anaemia, malignant infiltration of bone marrow, megaloblastic anaemia, chemotherapy, myelodysplasia
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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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Question 25
Incorrect
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The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Marginal sinus
Correct 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
- Physiology
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Question 26
Incorrect
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Which of the following statements is correct with regards to immunoglobulin?
Your Answer: Immunoglobulin molecules are composed of 4 identical light chains.
Correct Answer: The isotype of immunoglobulin is determined by the heavy chain.
Explanation:The composition of immunoglobulin molecules is two identical heavy and two identical light chains. These chains are linked by disulphide bridges and are each have highly variable regions which give the immunoglobulin its specificity. In addition, they have constant regions and there is virtual complete correspondence in amino acid sequence in all antibodies of a given isotype. Five isotypes of immunoglobulin exist – these are IgG, IgA, IgM, IgE and IgD. They are determined by the heavy chain (gamma, alpha, mu, epsilon or delta respectively). The light chains are either kappa or lambda.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 27
Incorrect
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Approximately what proportion of lymphocytes are B-cells:
Your Answer: 0.5
Correct Answer: 0.2
Explanation:B-cells (20% of lymphocytes) mature in the bone marrow and circulate in the peripheral blood until they undergo recognition of antigen. B-cell immunoglobulin molecules synthesised in the cell are exported and bound to the surface membrane to become the B-cell receptor (BCR) which can recognise and bind to a specific antigen (either free or presented by APCs). The BCR is also important for antigen internalisation, processing and presentation to T helper cells. Most antibody responses require help from antigen-specific T helper cells (although some antigens such as polysaccharide can lead to T-cell independent B-cell antibody production). When the B-cell is activated, the receptor itself is secreted as free soluble immunoglobulin and the B-cell matures into a memory B-cell or a plasma cell (a B-cell in its high-rate immunoglobulin secreting state). Plasma cells are non-motile and are found predominantly in the bone marrow or spleen. Most plasma cells are short-lived (1 – 2 weeks) but some may survive much longer. A proportion of B-cells persist as memory cells, whose increased number and rapid response underlies the augmented secondary response of the adaptive immune system.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 28
Incorrect
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What proportion of peripheral blood leukocytes are monocytes?
Your Answer: 12 - 15%
Correct Answer: 5 - 10%
Explanation:Monocytes account for around 5 to 10% of peripheral white cells. Monocytes in peripheral blood are generally bigger than other leukocytes and feature a large central oval or indented nucleus with clumped chromatin. The abundant cytoplasm staining blue and containing numerous fine vacuoles gives the appearance of ground glass. Cytoplasmic granules are another type of granule. Monocytes evolve from the granulocyte-macrophage progenitor to become monoblasts, promonocytes, monocytes, and tissue macrophages (in increasing order of maturity). Monocytes only stay in the bone marrow for a short time before exiting to circulate in the bloodstream for 20-40 hours before becoming macrophages.
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This question is part of the following fields:
- Immunology
- Pathology
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Question 29
Correct
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Question 30
Incorrect
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A 22-year-old man arrives at the emergency department with a sore throat, low-grade fever, and malaise. His partner has infectious mononucleosis, which was recently diagnosed. In this situation, which of the following cells is the most proliferative:
Your Answer:
Correct Answer: Lymphocytes
Explanation:Histologic findings in EBV infectious mononucleosis: Oropharyngeal epithelium demonstrates an intense lymphoproliferative response in the cells of the oropharynx. The lymph nodes and spleen show lymphocytic infiltration primarily in the periphery of a lymph node. Relative lymphocytosis (≥ 60%) plus atypical lymphocytosis (≥ 10%) are the characteristic findings of Epstein Barr virus (EBV) infectious mononucleosis.
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This question is part of the following fields:
- Immunology
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
