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Msb 103:Blood And Immune Mechanism Question Paper

Msb 103:Blood And Immune Mechanism

Course:Bachelor Of Medicine And Bachelor Of Surgery

Institution: Moi University question papers

Exam Year:2008

M O I U N I V E R S I T Y

SCHOOL OF MEDICINE

END OF TERM III EXAMINATION (ETE III) 2007/2008
COURSE: MSB 103: BLOOD & IMMUNE MECHANISM
PROGRAMME: M.B.Ch.B. YEAR OF STUDY: 1(ONE)
DATE: 13TH OCTOBER, 2008 TIME: 9.00 A.M. - 12.00 NOON

GENERAL INSTRUCTIONS:-

(I) WRITE YOUR UNIVERSITY REGISTRATION NUMBER ON EVERY PIECE OF PAPER YOU USE.

(II) DO NOT WRITE YOUR NAMES ON ANY PIECE OF PAPER YOU USE.

(III) THIS PAPER CONSISTS OF FOUR (4) SECTIONS, HEADED: SECTION A - HUMAN ANATOMY, SECTION B - MEDICAL BIOCHEMISTRY, SECTION C - MEDICAL PHYSIOLOGY, SECTION D - IMMUNOLOGY. ALL TO BE ANSWERED IN A TOTAL TIME OF THREE (3) HOURS.

IV) EACH SECTION CONSTITUTES A CAT RELATING TO THE DISCIPLINE NAMED.

V) ANSWER ALL THE QUESTIONS IN ALL THE FOUR (4) SECTIONS.

VI) QUESTIONS IN EACH SECTION MUST BE ANSWERED IN SEPARATE ANSWER BOOKLETS OR ANSWER SHEETS SO THAT THEY CAN BE HANDED IN SEPARATELY AT THE END OF THE EXAMINATION.

(IV) READ CAREFULLY THE ADDITIONAL INSTRUCTIONS PRECEEDING EACH SECTION.

SECTION A: HUMAN ANATOMY (20 Minutes)

PART I: GROSS ANATOMY (Only for Medical Students)
MULTIPLE CHOICE QUESTIONS (MCQs) (5 Minutes)
TYPE 3
INSTRUCTIONS

(I) EACH OF THE QUESTIONS IN THIS SECTION CONSISTS OF A STATEMENT/QUESTION WHOSE MOST APPROPRIATE COMPLETION/ANSWER IS PROVIDED AMONG THE FIVE OPTIONS NUMBERED (a) - (e).

(II) FOR EACH QUESTION SELECT THE MOST APPROPRIATE OPTION AND INDICATE BY PRINTING AN X IN THE APPROPRIATE BOX IN THE ANSWER SHEETS PROVIDED.

(III) CHOOSE THE WRONG STATEMENT.

1. The muscles supplied by the ulnar nerve in the hand include:

a) The flexor digiti minimi.
b) The abductor digiti minimi.
c) The first lumbrical muscle.
d) The opponents digiti minimi.
e) The adductor policis.

2. The structures passing superficial to the flexor retinaculum are:

a) Ulnar nerve.
b) Ulnar artery.
c) Radial nerve.
d) Tendon of palmaris longus.
e) Palmar cutaneous branch of median nerve.

3. The dorsal digital expansion of the index finger receives the tendons of:

a) The extensor digitorum.
b) One lumbrical.
c) Two dorsal interossei.
d) One palmar interosseous.
e) The extensor indicis.

4. The interossei musles:

a) The dorsal are four.
b) The palmar usually are three.
c) All are inserted into the extensor expansion.
d) The palmar muscles abduct the fingers.
e) All are supplied by the deep branch of the ulnar nerve.

5. The following structure are among the contents of the extensor retinaculum compartments:

a) The abductor policis longus in the first.
b) The extensor carpi radialis brevis in the second.
c) The anterior interosseous artery in the fourth.
d) The extensor digiti minimi in the fifth.
e) The extensor carpi ulnaris in the sixth.

PART II: HISTOLOGY AND EMBRYOLOGY

SUBSECTION A: MULTIPLE CHOICE QUESTIONS (MCQs) (10 Minutes)

TYPE 3

INSTRUCTIONS

(I) THERE ARE TEN (10) QUESTIONS IN THIS SECTION.

(II) ANSWER ALL THE TEN (10) QUESTIONS.

(III) CHOOSE THE WRONG STATEMENT IN EACH QUESTION.

1. Concerning hemopoiesis:

a) Stem cells of the bone marrow are pluripotential.
b) Differentiation of blood cells precursors is regulated by the hemopoetins.
c) The first histologically identifiable cells are promyelocytes and basophilic erythroblasts.
d) Growth factor stimulates mitotic activity of progenitor cells.
e) One CFU is common for the neutrophils and erythrocytes.

2. Regarding erythropoiesis:

a) The basophilia of the basophilic erythroblast is due to numerous mitochondria.
b) The polychromatophilic erythroblast has some amount of hemoglobin.
c) The oxyphilia of the orthochromatic erythroblast is due to richness in hemoglobin.
d) The nucleus is extruded at the stage of late normoblast.
e) The reticulocytes constitute about 1% of erythrocytes.

3. In relation to granulopoiesis:

a) One myeloblast is common for all granulocytes.
b) The first specific granules appear at the stage of myelocyte.
c) The neutrophilic metamyelocyte has norse-shoe shaped nucleus.
d) The nuclei of promyelocytes are located peripherally.
e) The process of segmentation of nuclei beging at the stage of metamyelocyte.

4. About development and structure of lymphocytes:

a) Stimulated B-lymphocytes are transformed into the plasmablasts.
b) B lymphocytes can be differentiated from the T lymphocytes in the blood film.
c) Medium-sized lymphocytes may be found within peripheral blood.
d) The surface of the B lymphocyte shows numerous microvilli under the electron microscope.
e) T lymphocytes may be transformed into the T immunoblasts.

5. Regarding development and structure of the monocytes and platelets:

a) CFU is common for the neonocytes and granulocytes.
b) The monoblast has similar morphological characteristics with myeloblasts.
c) The platelets are fragments of the megakaryocytes.
d) The number of platelets is about 10 thousand per 1ml3.
e) The monocytes become active phagocytes within connective tissue after leaving blood vessels.

6. Concerning bone marrow:

a) It is the first organ producing blood cells during embryogenesis.
b) The capillaries of the bone marrow are of the fenestrated type.
c) The bone marrow is taken from the sternum with diagnostic purpose.
d) The stroma of the red bone marrow consists of reticular cells.
e) The peripheral lymphoid organs are populated by the lymphoblasts originated from the bone marrow.

7. In relation to the thymus:

a) In adults, the thymus is completely replaced by the adipose tissue.
b) The stroma of the organ is composed of epithelio-reticular cells.
c) Aging involution of the gland is not reversible.
d) Hassal’s corpuscles consist of epithelial cells with the signs of degeneration.
e) Thymosin stimulates maturation of T lymphocytes.

8. About spleen:

a) PALS consists of T lymphocytes.
b) The splenic cords are inserted among the sinusoids.
c) The syderophages engulf hemoglobin from the destroyed erythrocytes.
d) The thick capsule of the spleen is composed of dense fibrous tissue without smooth muscle cells.
e) There are gaps among the endothelial cells of sinusoids through which the blood cells can pass.

9. Regarding lymph nodes:

a) The medullary cords are composed of small lymphocytes and plasma cells.
b) The paracortex consists of B lymphocytes.
c) The stroma of lymph nodes is represented by the reticular tissue.
d) The subcapsullar sinus continues with the interfollicular sinus.
e) The high endothelial venules of the paracortex are devoid of smooth muscle cells.

10. Concerning MALT:

a) The Peyer’s patches of ileum are composed of B lymphocytes only.
b) The lymphoid follicles of appendix are separated from the adjacent structures by the fibrous capsule.
c) The lymphoid follicles of the palatine tonsils are embedded into the diffuse lymphoid tissue.
d) The crypts of tonsils contain live and dead lymphocytes, bacteria and desquamated epithelial cells.
e) The lymphoid follicles can penetrate lamina muscucaris mucosae and infiltrate submucosa of large intestine.

SUBSECTION B: LONG ESSAY QUESTION (LEQ) (15 Minutes)

INSTRUCTIONS:

I) THIS PART CONSISTS OF ONE (1) QUESTION.

II) ANSWER THE QUESTION.

LEQ 1. Give the classification of the leucocytes, describe their morphology and functions.
(15 minutes)

SECTION B: MEDICAL BIOCHEMISTRY (35 Minutes)

PART I: MULTIPLE CHOICE QUESTIONS (MCQs) (20 Minutes)
TYPE III

INSTRUCTIONS:-

(I) EACH OF THE QUESTIONS IN THIS SUBSECTION CONSISTS OF A STATEMENT/QUESTION WHOSE MOST APPROPRIATE COMPLETION/ANSWER IS PROVIDED AMONG THE FIVE OPTIONS NUMBERED (a) - (e).

(II) FOR EACH QUESTION SELECT THE MOST APPROPRIATE OPTION AND INDICATE BY PRINTING AN X IN THE APPROPRIATE BOX IN THE ANSWER SHEETS PROVIDED. IF YOU DO NOT KNOW THE ANSWER, PRINT X IN THE BOX IN THE `DK'' COLUMN

(III) A CORRECT RESPONSE EARNS YOU ONE MARK.

1. Which one of the following is not a feature of myoglobin?

a) It possesses hemeprosthetic group.
b) It is a single polypeptide chain.
c) It has a tetrameric structure.
d) It is a globular protein.
e) It has a tertiary structure.

2. The function of Mb in humans is to transport:

a) CO2 in peripheral tissues.
b) H+ in peripheral tissues.
c) O2 in peripheral tissues.
d) O2 to all pants of the body.
e) O2 within muscle.

3. The predominant glycosaminoglycan in synovial fluid is:

a) Hyaluronate.
b) Dermatan sulfate.
c) Heparan sulfate.
d) Chondroitin sulfate.
e) Heparin sulfate.

4. Which of the following types of glycosaminoglycans does not contain sulfate group?

a) Keratan sulfate.
b) Hyaluronate.
c) Heparan sulfate.
d) Dermatan sulfate.
e) Chondroitin sulfate.

5. The amino acid composition of collagen consists of all of the following except:

a) Lysine.
b) Glycine.
c) Proline.
d) Hydroxyproline.
e) Hydroxylysine.

6. Sickle-cell hemoglobin is due to:

a) Presence of valine instead of glutamate at position 6 of a-chain.
b) Reduced synthesis of ? chain.
c) Presence of tyrosine instead of proximal histidine.
d) Presence of valine instead of glutamate at position 6 of ?-chain.
e) Presence of sickle cell disease.

7. Reduction of bilirubin in intestine yields:

a) Urobilinogen.
b) Porphobilinogen.
c) Stercobilinogen.
d) Biliverdin.
e) Verdoglobin.

8. Mucin glycoproteins are found in extracellular secretions linked to N-acetylgalactosamine via:

a) Asparagine side chain.
b) Serine side chain.
c) Glycine side chain.
d) Lysine side chain.
e) Arginine side chain.

9. Which of the following gycosaminoglycans does not contain glucoronic acids?

a) Keratan sulfate.
b) Heparan.
c) Dermatan.
d) Chondroitin.
e) Heparin.

10. Elastin has a very low content of:

a) Hydroxyproline.
b) Isoleucine.
c) Leucine.
d) Alanine.
e) Valine.

11. Which of the following statements about heme is incorrect?

a) It has iron in oxidative state 2.
b) It has one vinyl group.
c) It has two polar propionate substituents.
d) It binds oxygen.
e) It is a cyclic tetrapyrrole.

12. Which one of the following is not a normal hemoglobin?

a) HbM.
b) HbA.
c) HbA2.
d) HbF.
e) HbF2.

13. All of the following are function of glycosaminoglycans except:

a) They serve as structural components of plasma membrane.
b) They serve as endoskeletal structures of bones.
c) They are storage forms of polysaccharides.
d) They serve as lubricants of extracellular matrix.
e) They act as anticoagulants.

14. The roles of plasma glycoproteins include all of the following except as:

a) Lubricants of blood vessels.
b) Complement proteins for IgG.
c) Complement proteins for IgG.
d) Complement proteins for Iga.
e) Facilitators of freezing resistance of cold water fish.

15. The predominnat amino acid in keratin is:

a) Cystine.
b) Proline.
c) Lysine.
d) Valine.
e) Alanine.

16. The precursors of heme synthesis are:

a) Glycine and s-aminolevulinate.
b) Succinyl CoA and lycine.
c) Glycine and lysine.
d) S-Aminolevalinate and lysine.
e) Succinyl CoA and lysine.

17. During the catabolism of heme CO is released in the presence of:

a) Bilirubin reductase.
b) Ferrochelatase.
c) Heme oxidase.
d) Heme dehydrogenase.
e) Heme oxygenase.

18. Under normal conditions mucin glycoproteins would not be expected to be present in:

a) Saliva.
b) Mucus of the nose.
c) Female genital tract.
d) Blood serum.
e) GIT.

19. Human glycoproteins contain all of the following sugars except:

a) Xylose.
b) N-acetylgalactosamine.
c) N-acetylglucosamine.
d) Fucose.
e) Rhmnose.

20. Type III collagen is predominantly present in:

a) Cartilages.
b) Skin.
c) Tendons.
d) Teeth.
e) Bones.

PART II: SHORT ANSWER QUESTION (SAQ) (10 Minutes)

INSTRUCTIONS:

I) THERE IS ONE (1) QUESTION IN THIS SECTION.

II) ANSWER THE QUESTION.

SAQ 1. Draw the structure of a repeating unit of hyaluronic acid and outline its functions.

SECTION C: MEDICAL PHYSIOLOGY (50 Minutes)

SUBSECTION C(i) : MULTIPLE CHOICE QUESTIONS (MCQ) (20 Minutes)
TYPE 2

INSTRUCTIONS

(i) EACH OF THE QUESTIONS IN THIS SECTION HAS A STEM STATEMENT FOLLOWED BY FIVE COMPLETIONS NUMBERED (a) TO (e). A GIVEN COMPLETION, WHEN ADDED TO THE STEM STATEMENT MAY PRODUCE A COMPLETE STATEMENT THAT IS TRUE (T) OR FALSE (F).

(ii) INDICATE AGAINST THE APPROPRIATE NUMBERS IN THE ANSWER SHEETS PROVIDED WHETHER THE COMPLETE STATEMENTS IS TRUE (T) OR FALSE (F) BY PRINTING AN X IN THE BOX IN THE COLUMN HEADED T FOR TRUE OR F FOR FALSE.

(iii) IF YOU DO NOT KNOW WHETHER THE COMPLETE STATEMENT IS TRUE OR FALSE, PRINT THE X IN THE COLUMN HEADED D (FOR DO NOT KNOW).

(iv) A CORRECT RESPONSE EARNS YOU PLUS ONE MARK. AN INCORRECT RESPONSE EARNS MINUS ONE - HALF OF A MARK. AN X IN THE D COLUMN EARNS YOU ZERO MARK. ANY UNANSWERED OPTION COUNTS AS INCORRECT.

1. Erythropoiesis:

a) Is inhibited by androgens.
b) Is enhanced by thrombopoietin.
c) Is absent in the tibia of adults.
d) Is enhanced on diving into the sea.
e) Declines with age.

2. As concerns formation of blood:

a) Pluripotent stem cells differentiate into committed stem cells under the influence of hemopoietin.
b) Cellular components proliferate in response to infections.
c) In the fetus in derived mainly from maternal circulation.
d) Occurs daily.
e) Plasma is derived mainly from the liver.

3. As concerns granulocytes:

a) Basophils are about 10% of all circulating leucocytes.
b) Neutrophils generate acids that digest bacteria.
c) Eosinophls degranulate to release heparin.
d) Some granulocytes participate in the blood clotting mechanism.
e) Are motile cells.

4. Lymphocytes:

a) Of the TH – subtype secrete immunoglobulins.
b) In circulation are increased by physiological stress.
c) Enter the circulation primarily from the bone marrow.
d) Mediate delayed-type hypersensitivity reactions.
e) Are involved in recognition of sely.

5. As concerns plasma proteins:

a) Account for oncotic pressure of about 45 mmHg in an average capillary.
b) Are all synthesized in the liver.
c) Concentration declines during starvation.
d) Transport drugs in circulation.
e) Are lost in urine.

6. Platelets:

a) Have a half life of about 6 days in circulation.
b) Mainly secrete vasodilators.
c) Regulate circulating levels of polymorphonuclear lymphocytes.
d) Concentration declines on ascending a mountain.
e) May initiate intravascular clotting.

7. With respect to normal red blood cell induces:

a) Normal red blood cells are lysed in 5% glucose solution.
b) Mean cell diameter increased during menstruation.
c) Mean cell hemoglobin concentration is the same in males and females.
d) Normal reticulocyte count range from 0.2 – 2%.
e) Haematocrit is estimated from a drop of blood obtained from a finger prick.

8. As concerns blood groups:

a) D agglutinins are inherited from the parents.
b) An AB+ mother cannot have an O- child.
c) Agglutinogen D is only found on the membrane of red blood cells.
d) An O+ recipient may cross-react with an O+ donor.
e) ABO system develops after birth.

9. Blood clotting:

a) May be initiated by accumulation of Ca2+.
b) Is enhanced by consumption of vitamin K.
c) Is deficient when platelet counts are 100,000/µl of blood.
d) Time is about 10 minutes.
e) May occur in intact blood vessels.

10. Hemoglobin:

a) Is mainly synthesized in the liver.
b) May be found outside red blood cells.
c) Affinity for oxygen is increased by oxidizing agents.
d) Contains eight polypeptide chains and a porphyrin ring.
e) Participants in blood buffering of acids and bases.

11. The intrinsic pathway of blood clotting.

a) Is triggered by release of tissue thromboplastin.
b) Requires factor XIIa for full activation.
c) Is inhibited by thrombomodullin.
d) May be initiated by collagen exposure.
e) May be inhibited by elimination of Ca2+.

12. Acquired immunity:

a) Is specific to invading organisms.
b) Is involved in graft tissue rejection.
c) Is deficient in young children.
d) Is mediated by natural killer cells.
e) Involves release of the complement proteins.

13. The following factors are essential for the stabilization of the fibrin clot:

a) Calcium ions.
b) Active factor 13.
c) Fibrinogen.
d) Platelet phospholipids.
e) Thrombin.

14. Bilirubin:

a) Of the unconjugated type causes uncoupling of oxidative phosphorylatton.
b) Is a green pigment.
c) Is derived from polypeptide chains of haemoglobin.
d) Is transported in blood wholly bound to albumin.
e) Normal level in blood in on average 30 µ Mol/L.

15. In a normal female human being, mature white blood cells:

a) Have an average diameter of about 80 micrometers.
b) Contain no nucleus.
c) Are about 9,000 – 11,000 cells/µl of blood.
d) Are removed from circulation within 10 days.
e) Concentration shows diurnal variation.

16. During red blood cell development:

a) Synthesis of Hb begins at the reticulocyte stage.
b) Vitamin B6 enhances development of red blood cells.
c) Bleeding enhances maturation of red blood cell precursors.
d) Absence of glucose causes malformation.
e) Mature red blood cells do not contain DNA.

17. Basophils:

a) Are involved in hypersensitivity reactions.
b) Make up about 0 – 5% of total white blood cells in a normal WBC differential count.
c) Kill invading organisms by phagocytosis.
d) Are abundant beneath mucousal surfaces in the gastrointestinal tract.
e) Are involved in lymphocyte activation.

18. The following substances form insoluble precipitates with calcium:

a) Ethelenediamine tetra acetic acid (EDTA).
b) Citrates.
c) Heparin.
d) Warfarin.
e) Oxalates.

19. Hazards of blood transfusion include:

a) Hypothermia.
b) Development of fever.
c) Toxicity.
d) Allergic reactions.
e) Hemolytic reactions.

20. The following types of cells are involved in production of plasma protens:

a) Neurons.
b) Plasma cells.
c) Skeletal muscle cells.
d) Hepatocytes.
e) Enterocytes.

PART II: SHORT ANSWER QUESTIONS (SAQs) (30 Minutes)

INSTRUCTIONS:

I) THERE ARE THREE (3) QUESTIONS IN THIS SECTION.

II) ANSWER THE THREE (3) QUESTIONS.

III) START EACH QUESTION ON A FRESH PAGE OF THE BOOKLET.

SAQ 1. Write short notes on hemopolesia:
(10 minutes)

SAQ 2. Explain the functions of white blood cells.
(10 minutes)

SAQ 3. Explain the significance of blood indices.
(10 minutes)

SECTION D: IMMUNOLOGY (50 Minutes)

PART I: MULTIPLE CHOICE QUESTIONS (MCQS) (30 Minutes)

INSTRUCTIONS:-

(i) THIS PAPER IS MADE UP OF TWO (2) SUBSECTIONS: I AND II. SUBSECTION I CONSISTS OF THIRTY (30) MULTIPLE CHOICE QUESTIONS (MCQs) TO BE ANSWERED IN FORTY (40) MINUTES. SUBSECTION II CONSISTS OF TWO (2) SHORT ANSWER QUESTION (SAQs) TO BE ANSWERED IN THIRTY (30) MINUTES.

(ii) FOR THE MCQs, EACH QUESTION CONSISTS OF A STATEMENT/STEM WHOSE MOST CORRECT RESPONSE IS PROVIDED AMONG THE FIVE OPTIONS NUMBERED A TO E.

(iii) FOR EACH MCQ, SELECT ONLY ONE APPROPRIATE OPTION AND INDICATE BY CIRCLING IT.

EXAMPLE:

Major features of innate immunity include
(a) recognition
(b) specificity
(c) memory
d first line of defense
(e) adaptability
The most appropriate response is d

(iv) ATTEMPT ALL QUESTIONS IN THE TWO SUBSECTIONS.

SUBSECTION DI: MULTIPLE CHOICE QUESTIONS (MCQs) (30 minutes)

1. Which one of the following is not true about the NK cells?

a) They produce IFN which activates macrophages.
b) IL 10 and TGF-? negatively regulate NK cells.
c) IFN & I?, IL–15, IL-18 and IL-12 induces activity of NK cells.
d) Th2 cytokines enhance activity of NK cells.
e) All of the above.

2. Which one of the following control complement system activation?

a) Factor B.
b) C3b.
c) MAC.
d) Immune complexes.
e) Factor I.

3. VDJ recombination takes place in:

a) Spleen.
b) Lymph nodes.
c) Bone marrow.
d) Tonsils.
e) Liver.

4. B cells differ from the other professional APC because B cells:

a) Use B7 as their constimulatory molecule.
b) Present only peptides from antigens they bind with their membrane Ig.
c) Present exogenous antigen to T cells. On class II MHC.
d) Activate T cells in the secondary lymphoid organs.
e) None of the above is true.

5. T cells which activate macrophages do all of the following EXCEPT:

a) Activate macrophage at the site of infections.
b) Activate only macrophages presenting specific antigen on MHC.
c) Have CD4 on their cell membrane.
d) Become armed effector cells in response to antigen plus co-stimulation.
e) Produce granzymes that macrophages use to kill vesicular pathogens.

6. Immature B cells express:

a) Cytoplasmic IgM.
b) Surface IgM.
c) IgD.
d) IgM and IgD.
e) IgM heavy chains only.

7. Th1 cells promote cellular immunity by secreting:

a) IL-1 and IL-6.
b) IL-2 and IFN?.
c) IL-4 and IL-5.
d) IL-10 and IL-12.
e) TNF a and FasL.

8. Which of the following is not part of the process of negative selection?

a) Anergy.
b) Selection of B cells that are able to bind to antigens.
c) Apoptosis.
d) Receptor editing.
e) All of the above.

9. Which of the following is the most potent in activation of classical complement pathway?

a) IgA.
b) IgE.
c) IgD.
d) IgG.
e) IgM.

10. In the activation of CD4 T cells antigen signal is delivered through:

a) HLA-DP-TCR peptide complex.
b) CD28 – CD80/86 – peptide complex.
c) CD3 – TCR – CD28 – peptide complex.
d) HLA – DP – DR and DQ molecules.
e) CD3 CD4/CD28 – TCR – MHC peptide complex.

11. Which of the following are Th2 cytokines?

a) IL1, IL-2, IL-10, IL-18.
b) IFN?, IL-5, IL-6, IL-2.
c) IL4, IL-5, IL-10, IL-13.
d) IL4, IL-10, IL-13, IL-2.
e) IL-18, IL-5, IL-6, IL-2.

12. Alternative pathway proteins include all of the following EXCEPT:

a) Factor B.
b) C1.
c) C3.
d) Properdin.
e) Factor D.

13. Which of the following is a complement lytic factor?

a) C5b – 9.
b) Clq.
c) C2a.
d) C4b.
e) Factor –H.

14. Granulomas:

a) Are commonly found in tissues infected with viruses.
b) Contain infected T cells surrounded by macrophages.
c) Contains infected macrophages surrounded by T cells.
d) Are granunocyte tumours.
e) Are a sign that the body has successfully eliminated all pathogen.

15. Antibody exert feedback control on the immune responses in the following way EXCEPT:

a) Passively administered IgM together with an antigen enhances the immune response.
b) IgG suppress specific IgG synthesis by antibody blocking and receptor cross-linking.
c) Immune complexes may enhance or suppress immune response using FC-dependent mechanism.
d) Anti-idiotypic antibodies cannot down-regulate the immune response.
e) None of the above.

16. Cytokines are:

a) High molecular weight glycoproteins.
b) Pleiotropic.
c) Not redundant.
d) Not multifunctional.
e) Produced by only mitogen activated leukocytes.

17. Cl inhibitor controls complement activation by:

a) Binding to MAC.
b) Dissociating formed C3.
c) Inhibiting clr and Cls enzyme active sites.
d) Enhancing decay of MAC.
e) Preventing Factor H and Factor I activity.

18. Membrane events required fo Th activation include all of the following EXCEPT binding of T cell:

a) CD4 to APC class II MHC.
b) CTLA-4 to APC B7.
c) High affinity IL-2 receptor to IL-2.
d) LFA-1 to APC ICAM.
e) TCR to peptide on APC class II MHC.

19. One of the following cytokines enhances proliferatin of T cells:

a) IL-1.
b) IL-4.
c) IL-2.
d) IFN-d.
e) IFN-?.

20. The primary immunoglobulin involved in allergic reactions is:

a) IgE.
b) IgA.
c) IgD.
d) IgM.
e) IgG.

21. Memory T cells express the following markers:

a) CD45RO.
b) CD56.
c) CD45RE.
d) CD3 and CD1.
e) CD45 R A.

22. Armed effector T cells differ from naïve T cells inthat effector cells:

a) Are not antigen – specific.
b) Have CD28 instead of CTLA-4 to bind B7.
c) Do not need to bind co-stimulatory molecules.
d) Do not need to bind peptide plus MHC.
e) Do not use CAM to bind other cells.

23. Once T cells have received antigen plus co-stimulatory signals, they divide in response to IL-2 secreted by:

a) B cells.
b) Dendritic cells.
c) APC presenting the peptide.
d) T cells.
e) Macrophages.

24. Which of the following is not involved in class switching?

a) IL-4.
b) IL-5.
c) IFN-?.
d) CD40L.
e) NK cells.

25. Dendritic cells are the best APCs for activating:

a) CD8 CTLs.
b) CD4 / helper T cells.
c) Th2 cells.
d) Th1 cells.
e) Naïve T cells.

26. Cell-mediated immunity:

a) is the same as innate immunity.
b) Is mediated by B and T cells.
c) Is mediated by T cells, macrophages and interleukins.
d) Is mediated by armed effector T cells and B cells.
e) Is mediated by antibodies and interleukins.

27. Antibodies enhance pathocytosis through:

a) Triggering mast cell degranulation.
b) Opsonization.
c) Neutralizing toxins.
d) Activating ADCC.
e) Activating B cells.

28. Cellular immunity protects the body in the following ways EXCEPT:

a) Activate macrophages to kill phagocytosed bacteria.
b) Induction of apoptosis by CD8 T cells. Using Fas – FasL binding.
c) Complement mediated lysis of bacterial cells.
d) MHC restricted cytotoxicity killing virus – infected cells.
e) NK cells performing natural killing of tumour cells.

29. CD40 on macrophages binding to CD40L on Th1 cells signals the macrophages to:

a) Phagocytose the Th1 cells.
b) Secrete IL-2.
c) Die.
d) Kill cytoplasmic viruses.
e) Respond to IFN? by expressing more membrane MHC.

30. Most of the intrathymic death of potential T cell subsets is due to:

a) Apoptosis.
b) Necrosis.
c) Phagocytosis.
d) Pinocytosis.
e) MHC-restriction.

PART II: SHORT ANSWER QUESTIONS (SAQs) (20 minutes)

INSTRUCTIONS:

I) THERE ARE TWO (2) QUESTIONS IN THIS SECTION
II) ANSWER THE TWO (2) QUESTIONS
III) START EACH QUESTION ON A FRESH PAGE OF THE BOOKLET OR PAPER.

SAQ 1. Describe the process of T cell development in the thymus.
(10 minutes)

SAQ 2. With the aid of a diagram describe the structure of an IgG molecule.
(10 minutes)

Msb 103:Blood And Immune Mechanism Question Paper

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