Exam questions 12, 13

Question 1

Cytokine action on cells

Answer 1

A cytokine acts on a cell if the cell expresses the corresponding receptor. TNF binds TNFR, activating NF-κB or triggering apoptosis.

Question 2

Cytokine response detection methods

Answer 2

qRT-PCR/PCR (mRNA detection), ELISA (protein levels), Flow Cytometry (intracellular proteins), Bioassays (functional activity).

Question 3

IL-1β production mechanism

Answer 3

Pro-IL-1β is transcribed via NF-κB, cleaved by caspase-1, and secreted after inflammasome activation.

Question 4

Cytokine regulation methods

Answer 4

Short half-life, decoy receptors, antagonists (e.g., IL-1Ra), post-translational modifications.

Question 5

T lymphocytes and antigen encounter

Answer 5

T cells meet antigens in lymph nodes, transported by APCs from the infection site.

Question 6

B vs T cell antigen recognition

Answer 6

B cells recognize native antigens, T cells recognize processed antigens on MHC.

Question 7

B-cell activation (TD and TI antigens)

Answer 7

TD requires T-helper cell interaction, TI activates B-cells via BCR crosslinking or co-receptors.

Question 8

Thymic T-cell selection

Answer 8

Positive selection for self-MHC recognition, negative selection to eliminate self-reactive T-cells.

Question 9

TCR gene rearrangement

Answer 9

TCR β-chain undergoes V-DJ joining, α-chain V-J joining, RAG proteins mediate recombination, allelic exclusion.

Question 10

MHC I and MHC II expression

Answer 10

MHC I on all nucleated cells for intracellular antigens, MHC II on APCs for extracellular antigens.

Question 11

MHC I vs MHC II peptides

Answer 11

MHC I binds short peptides (8-10 amino acids), MHC II binds longer peptides (13-18 amino acids).

Question 12

MHC molecules as “protein fingerprints”

Answer 12

MHC presents peptides from the cell’s protein turnover, reflecting its environment.

Question 13

MHC molecules as “promiscuous”

Answer 13

MHC molecules bind various peptides fitting structural constraints.

Question 14

MHC prediction algorithms

Answer 14

Based on anchor residues and peptide spacing for computational predictions.

Question 15

KIRs on NK cells

Answer 15

KIRs inhibit NK cells by recognizing MHC I molecules

Question 16

NK cell killing mechanism

Answer 16

NK cells induce apoptosis via perforin/granzyme release and death receptor activation.

Question 17

Cardinal signs of inflammation

Answer 17

Heat (calor), Redness (rubor), Swelling (tumor), Pain (dolor), Loss of function (functio laesa).

Question 18

Host defense in wound infection

Answer 18

Complement activation, neutrophil recruitment, cytokine release, antigen presentation, adaptive immunity activation.

Question 19

Adaptive response to mycobacteria

Answer 19

Th1 response with IFN-γ, IL-12, macrophage activation, CTL activation for infected cells.

Question 20

Desirable vaccine properties

Answer 20

Immunogenicity, long-term memory, safety.

Question 21

Adjuvant effect

Answer 21

Enhances immune response by activating PRRs and stimulating cytokine production.

Question 22

TLR-induced pathways

Answer 22

MyD88 pathway activates NF-κB for inflammation, TRIF pathway activates IRF for type I interferons.

Question 23

Autoimmune hemolytic anemia mechanism

Answer 23

Autoantibodies target RBCs

Question 24

Hypogammaglobulinemia

Answer 24

Deficiency in antibody production, leading to recurrent bacterial infections.

Question 25

Wound infection host defense steps

Answer 25

Complement activation, neutrophil recruitment, cytokine release, antigen presentation, adaptive immunity.

Question 26

LPS recognition by immune cells

Answer 26

LPS binds TLR4-MD2 complex, activating NF-κB and IRF3 for cytokine production.

Question 27

IL-1β production

Answer 27

TLR activation induces pro-IL-1β, inflammasome activation cleaves it to mature IL-1β.

Question 28

Adjuvancy explanation

Answer 28

Enhances immune response by stimulating PRRs and providing co-stimulatory signals.

Question 29

KIRs function on NK cells

Answer 29

Inhibit NK activity through MHC I recognition

Question 30

NK cell target killing mechanisms

Answer 30

Perforin/granzyme pathway and death receptor activation induce apoptosis in target cells.

Question 31

B-cell activation by thymus-dependent antigens

Answer 31

T-helper cell interaction and CD40-CD40L signaling trigger B-cell activation and differentiation.

Question 32

Antibody structure and function

Answer 32

Y-shaped structure, Fab region for antigen binding, Fc for effector functions (e.g., opsonization, complement activation).

Question 33

Class switching mechanism

Answer 33

AID deaminates cytosines, DNA breaks are repaired, leading to new antibody isotype.

Question 34

TCR diversity mechanisms

Answer 34

V(D)J recombination during T-cell development, junctional diversity via N-nucleotide addition.

Question 35

Effector T-cell subsets

Answer 35

CD4+ T-cells: Th1, Th2, Th17, Treg. CD8+ T-cells: Cytotoxic T lymphocytes (CTLs).

Question 36

Th1 vs Th2 balance

Answer 36

Th1 promotes cell-mediated immunity, Th2 promotes humoral immunity.

Question 37

Immune response against viruses

Answer 37

Th1 responses and CTL-mediated killing of infected cells.

Question 38

Type I interferons in antiviral defenses

Answer 38

Induces antiviral states, enhances NK and CTL activity, upregulates MHC I.