IMY521S - IMMUNOLOGY - 1ST OPP - NOVEMBER 2024


IMY521S - IMMUNOLOGY - 1ST OPP - NOVEMBER 2024



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nAm I BIA un IVERSITY
OFSCIEnCEAno TECHnOLOGY
FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURALRESOURCES
DEPARTMENTOF CLINICALHEALTHSCIENCES
QUALIFICATION: BACHELOROF MEDICALLABORATORYSCIENCES
QUALIFICATIONCODE:08BMLS
COURSECODE: IMY5215
LEVEL:5
COURSENAME: IMMUNOLOGY
SESSION: NOVEMBER 2024
PAPER:
THEORY
DURATION: 3 HOURS
MARKS:
100
EXAMINER(S)
MODERATOR:
FIRSTOPPORTUNITYEXAMINATION PAPER
Mr FILIPPUSTSHAVUKA
Ms FREDRIKAENGELBRECHT
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
4. For section A, use the zip-grade answer sheet provided and use a pencil
to fill-out one correct answer
THIS QUESTION PAPERCONSISTSOF 13 PAGES(Including this front page).

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SECTION A: MULTIPLE CHOICE QUESTIONS
[30 MARKS]
QUESTION 1
[30]
Evaluate the statements in each numbered section and select the most appropriate
answer or phrase from the given possibilities. Answer all your questions on the
ZiP-grade answer sheet attached to the back of question paper.
1.1. What role did the English physician Edward Jenner played in the evolution of
immunology?
(1)
A. He is the father of pasteurisation.
B. He is the father of variolation.
C. He developed a vaccine against smallpox from milkmaids suffering from cowpox.
D. He discovered the complement system.
1.2. Which statement is true of the adaptive, but not the innate immune response?
(1)
A. Pathogens have evolved to fight it.
B. The receptors are highly specific.
C. Many cells work together to coordinate the response.
D. It fights both viruses and bacteria.
1.3. Monocytes move from the systemic circulatory system into general connective
tissues, where they differentiate into what phagocytic cell type?
(1)
A. Neutrophil
B. Macrophage
C. Plasma cell
D. Tcell
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1.4. Which of the following cell types of the innate immune system does not perform
phagocytosis?
(1)
A. Basophil
B. Neutrophil
C. Macrophages
D. Eosinophils
1.5. Myeloid leukaemia are caused by the cancerous production of innate (non-specific)
immune system cells. Identify the tissue in which such production is most likely to
occur. -
(1)
A. Thymus
B. Spleen
C. Lymph nodes
D. Bone marrow
1.6. Recognition of self vs. non-self by the adaptive immune system in humans is
accomplished in which ofthe following ways?
(1)
A. Exposure of B cells to the body's own antigens in the thymus
B. Exposure of B cells to the body's own antigens in the bursa of fabricius.
C. Exposure of T cells to the body's own antigens in the bursa of fabricius.
D. Exposure ofT cells to the body's own antigens in the thymus.
1.7. Which portion of an antibody provides antigen-binding sites?
(1)
A. Light chain
B. Heavy chain
C. Variable region
D. Constant region
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1.8. Which of the following is a feature of Natural killer cells?
(1)
A. They secrete natural lgM antibodies.
B. Upon activation they secrete abundant IL4.
C. They kill virally infected cells by a perforin-granzyme dependent mechanism.
D. They are activated by recognizing microbial peptides presented by MCH class I.
1.9. What happens when immune cells fail to eradicate Mycobacterium tuberculosis?
(1)
A. The immune cells completely destroy the bacteria.
B. The immune system forms a granuloma.
C. The bacteria immediately die.
D. The immune system releases antibodies to neutralize the bacteria.
1.10. The percentage of human peripheral blood T-cells bearing a gamma delta T-cell
receptor is:
(1)
A. 30-80%
B. 5%-10%
C. 100%
D. 0%
E. Only present during mycobacterial tuberculosis infections.
1.11. The T-cell receptor (TCR)antigen recognition signal is transduced by:
(1)
A. TCRalpha chain
B. TCR beta chain
C. CO2
D. CD3
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1.12. Antigen-recognizing receptors differ in their affinity for antigens, which can be
expressed in terms of their dissociation constant {Kd). Higher Kd values indicate
lower affinity for antigens. Given the following dissociation constants {Kd) for
different receptors, which one demonstrates the highest affinity for its antigen?
(1)
A. Antibody (lgG): Kd = 10- 9 M
8. T-cell receptor (TCR):Kd = 10- 5 M
C. MHC ClassI molecule: Kd = 10- 5 M
D. MHC Class II molecule: Kd = 10-4 M
1.13. A hapten is:
(1)
A. An epitope
8. A carrier
C. A Molecule that is too small to elicit an immune response
D. An immunogen that can elicit immune response
1.14. The following CD marker is found on surfaces of both 8- and T- lymphocytes.
(1)
A. CDllb
8. CD4
C. CDS
D. CDB
1.15. The following statements about the functions of cell markers are true EXCEPT:
(1)
A. Cell markers are responsible for directly neutralizing pathogens during immune
responses.
8. Cell markers help identify the lineage of a particular immune cell.
C. Cell markers play a role in the activation, communication and signalling of immune
cells.
D. Cell markers are used to distinguish between different stages of cell maturation.
5

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1.16. Which of the following is an example of a pathogen-associated molecular
pattern (PAMP) recognized by the innate immune system?
(1)
A. Double-stranded RNAfrom replicating viruses.
B. MHC molecules on mammalian cells.
C. lmmunoglobulin G (lgG) antibodies.
D. T-cell receptors (TCRs)on lymphocytes.
1.17. Which of the following is not one of the three main antigen-presenting cell types? (1)
A. Dendritic cells
B. Kupffer cells
C. Natural Killer cells
D. Macrophages
1.18. Central tolerance refers to which of the following processes?
(1)
A. Destruction of lymphocytes that are not specific for self-antigens.
B. Production of self-antigens that are specific for lymphocytes.
C. Destruction of self-antigens that are specific for lymphocytes.
D. Destruction of lymphocytes that are specific for self-antigens.
1.19. Some forms of autoimmune disease result from autoantibodies that bind to
receptors on the cell surface. Antibodies that bind to these receptors can cause
disease by:
(1)
A. Activating complement and causing cell lysis.
B. Blocking normal ligand binding to the receptor.
C. Providing persistent stimulation through the receptor that is not regulated
normally.
D. All of the above.
E. None of the above.
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1.20. What is the effect of increased recruitment of regulatory T cells (Tregs) in the
tumour microenvironment?
(1)
A. Enhancesthe immune system's ability to destroy tumour cells.
B. Stimulates cytotoxic T cells to attack the tumour.
C. Suppresses the immune response, allowing tumour cells to evade immune
detection.
D. Increases inflammation and draws more immune cells to the tumour.
1.21. The intermolecular forces which contribute to the interaction between antibody
and antigen:
(1)
A. Are all electrostatic.
B. Are all van der Waals.
C. Are all hydrophobic.
D. Are all hydrogen bonds.
E. Rely on a combination of the above.
1.22. A patient with a MHC class II deficiency (an example is the Bare Lymphocyte
syndrome):
(1)
A. will experience decreased viral susceptibility.
B. will have an excessof activated complement that binds to MHC class II+ cells.
C. will experience declines in T helper/Antigen Presenting Cells interactions and a
resulting immunodeficiency.
D. will develop an autoimmune disease called Bare Lymphocyte Adenopathy (BLA).
E. will have decreased insulin levels.
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1.23. Antigen processing for presentation by MHC class I molecules involves:
(1)
A. TAP1 and TAP2
B. Endocytosis of extracellular pathogen
C. Degraded peptide in the ranges of 10-20 amino acids
D. Associated with CLIPand DM molecules
1.24. Examples of Major histocompatibility complex (MHC) class II is:
(1)
A. HLA-A
B. HLA-DR
C. HLA-F
D. CD4
1.25. With regards to inheritance of MHC genes, what is meant by linkage disequilibrium? (1)
A. When a pair of alleles linked at a locus within the MHC are sometimes inherited at
a greater frequency than expected from the product of their individual
frequencies.
B. When an individual inherits 2 sets of chromosomes for MHC: one from the father
and one from the mother.
C. When a pair of MHC alleles at two different loci segregate independently.
D. When a pair of alleles at two different loci segregate independently.
1.26. Which of the following is required for an effective adaptive immune response?
(1)
A. Activation of resting neutrophils.
B. Activation of resting lymphocytes.
C. Activation of resting macrophages.
D. Activation of resting platelets.
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1.27. What is an example of a cytokine acting in a paracrine manner?
(1)
A. lnterleukin-2 (IL-2) stimulating T cells in the local environment.
B. Tumour Necrosis Factor-alpha (TNF-a) acting systemically on distant tissues.
C. Interferon-alpha (IFN-a) inducing an antiviral state in the same cell that
produces it.
D. lnterleukin-10 (IL-10) inhibiting the same cell that secretes it.
1.28. Which cytokine receptor family is involved in the JAK-STATsignaling pathway?
(1)
A. Tumour Necrosis Factor (TNF) receptor superfamily
B. Chemokine receptor family
C. Class I and Class II cytokine receptor families
D. Toll-like receptor family
1.29. Inflammation is one of the first signs of damage or infection. Which cells do you
expect to be the most numerous in a new inflammation?
(1)
A. Natural Killer cells
B. Neutrophils
C. Common myeloid progenitor
D. B cells
1.30. Which of the following is an example of damage-associated molecular patterns
released by dying or damaged self cells?
(1)
A. Lipopolysaccharide (LPS)
B. Heat shock protein (HPS)
C. Lipoteichoic acid
D. Mannose-rich oligosaccharides
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SECTIONB: STRUCTUREDQUESTIONS
[70 MARKS]
QUESTION2
[18]
Provide detailed notes and explanations on the following terms:
2.1. Inflammation
(2)
2.2. Hypersensitivity
(2)
2.3. The principles of vaccination in immunology and the types of vaccines.
(4)
2.4. Cytokines
(2)
2.5. Pleiotropism of cytokines
(2)
2.6. Autocrine properties of cytokines
(2)
2.7. Positive selection ofT lymphocytes
(2)
2.8. Somatic recombinations
(2)
QUESTION3
[6]
Indicate whether the following cells belong to the innate or adaptive immune system:
3.1. Langerhans cells
(1)
3.2. Plasma cells
(1)
3.3. Kupffer cells
(1)
3.4. T helper 17
(1)
3.5. Dendritic cells
(1)
3.6. Basophils
(1)
QUESTION4
[21]
Toll-like receptors, scavenger receptors and complement receptors are all pattern
recognition receptors of the innate immunity. With the aid ofthe diagram below, answer
the following questions.
IO

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Pathogenic bacteria
Extracellular ATP
CC)NF-KB
NACHT
LM"I NLRP3
PYO +
ASC CARD,.CO
+
Caspase-1
(Inactive)
NLRP3
lnllammas~
K•emux
Reactive oxygen
species
Endogenous crystals
(MSU,CPPD)
Exogenous crystals
(MSU, CPPD, Alum,
Asbestos,
Cholesterol)
Vlral DNA
Muramyl dlpepllde
\\
~~,Wl_~
Pro-lL1flgene
transcr1ptlon
Caspase-1
\\_(active)
~=:t>~IL-1~
Pro-IL1fl
Nucleus
Acute inflammation '
4.1. What are the functions of Pattern Recognition Receptors (PRRs)?
(4)
4.2. Tabulate the cellular locations of pattern recognition receptors of the innate immune
system and the type of pathogen associated molecular patterns which can be recognised
in each location, under the following headings:
(9)
Location
PRR
PAMP / DAMP
4.3. Discuss how the NOD-like (NLRP3) inflammasome is formed in the correct order, and how
it mediates acute inflammation.
(8)
11

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QUESTION 5
[10]
Before a microbe or parasite can invade the host and cause infection, it must first
successfully fight off the first line defence mechanisms of the body and penetrate the
surface epithelial layers, to establish disease. Explain what forms part of the first line
defence.
(10)
QUESTION 6
[6]
The thymus is a primary lymphoid organ. In HIV infection, the adaptive immune system
is compromised due to infected immune cells. Why do immune cells die or become
dysfunctional because of HIV infection?
(6)
QUESTION 7
[4]
The image below is a representation of the mucosa-associated lymphoid tissue (MALT) of
the stomach. Using this image as a guide, briefly describe the arrangement and components
of lymphoid tissue in MALT.
(4)
cm•"'''\\ VILLUS
CCL25
E-cadherin
Epithelium
l!)tracpithclial lymph
Mucous glycocalyx layer
I
Brush border
,.,, ..,.,.-,~,ffl\\'11~· ;:~~
Lamina propria
lymphocyte
LAMINA
PR0PRIA
HEV
12

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QUESTION 8
[5]
Natural killer (NK) cells are lymphocytes distinct from T and B cells that play important
roles in immune responses. Using the image below, explain two ways in which inhibitory
roles of NK cells play a role in tissue homeostasis.
(5)
Inhibitory receptor
engaged
ij) Inhibitory receptor
not engaged
Removal of
Activating phosphates
signals and Inhibition
Activating
signals
···""'®
C Multiple activating
receptors engaged
Activating
signals
Ineffective
removal of
phosphates
and Inhibition
..·""'®
Actl
rece
Llga
for
recap
Normal
autologous cell
j
NKcell
not activated;
no cell killing
·1.t 't//
-
l
Virus-Infected CGII
(class I MHC negatiVG)
Stressed cell with
lnducGd expression
of activating llgands
.,
. . o· . j•
~
NK cell activated;
killing of
Infected cell
0~
NK cell activated;
kllllng of
stressed cell
THE OF EXAMINATION PAPER [100 MARKS TOTAL]
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