Immunology- HMX
Innate Immunity
1. Q: What are the main types of pattern recognition receptors (PRRs) and
their ligands?
A: Toll-like receptors (TLRs) recognize PAMPs like LPS; NOD-like
receptors (NLRs) detect intracellular bacterial components; RIG-I-like
receptors detect viral RNA; C-type lectin receptors bind fungal
carbohydrates.
2. Q: How does the inflammasome contribute to innate immunity?
A: It activates caspase-1, leading to cleavage of pro-IL-1β and pro-IL-18
into their active forms, promoting inflammation.
3. Q: Describe the role of dendritic cells in bridging innate and adaptive
immunity.
A: Dendritic cells capture antigens, mature, migrate to lymph nodes, and
present antigen via MHC molecules to naïve T cells, initiating adaptive
responses.
4. Q: What is the function of natural killer (NK) cells?
A: NK cells recognize and kill virus-infected or tumor cells via missing-
self recognition and produce cytokines like IFN-γ to activate
macrophages.
5. Q: How do complement pathways get activated?
A: Classical pathway: antibody-antigen complexes; lectin pathway:
mannose-binding lectin binding pathogens; alternative pathway:
spontaneous hydrolysis of C3.
Adaptive Immunity
6. Q: What is somatic hypermutation and where does it occur?
A: Somatic hypermutation introduces point mutations in the variable
regions of immunoglobulin genes in germinal centers to increase
antibody affinity.
7. Q: Explain the difference between MHC class I and class II molecules.
A: MHC I presents endogenous peptides to CD8+ T cells; MHC II
presents exogenous peptides to CD4+ T cells.
, 8. Q: What cytokines drive differentiation of naïve CD4+ T cells into Th1
cells?
A: IL-12 and IFN-γ promote Th1 differentiation.
9. Q: How do regulatory T cells (Tregs) suppress immune responses?
A: Tregs suppress via cytokines like IL-10 and TGF-β and by cell
contact-dependent mechanisms involving CTLA-4.
10.Q: What is the role of activation-induced cytidine deaminase (AID)?
A: AID is critical for class switch recombination and somatic
hypermutation in B cells.
Immunogenetics and Antigen Recognition
11.Q: Describe V(D)J recombination.
A: It’s the somatic recombination process of variable (V), diversity (D),
and joining (J) gene segments in B and T cell receptor genes generating
receptor diversity.
12.Q: What enzyme initiates V(D)J recombination?
A: RAG1 and RAG2 recombinase enzymes.
13.Q: Explain positive and negative selection in the thymus.
A: Positive selection ensures T cells recognize self-MHC; negative
selection deletes strongly self-reactive T cells.
14.Q: How does cross-presentation differ from regular antigen presentation?
A: Cross-presentation is when exogenous antigens are presented on MHC
class I molecules to CD8+ T cells.
15.Q: What molecular interaction stabilizes the immunological synapse?
A: LFA-1 (on T cells) binding to ICAM-1 (on APCs).
Cytokines and Signaling
16.Q: What are the main functions of IL-2?
A: IL-2 promotes T cell proliferation, survival, and differentiation.
17.Q: Describe JAK-STAT signaling in immune cells.
A: Cytokine binding activates JAK kinases, which phosphorylate STAT
transcription factors that dimerize and regulate gene expression.
18.Q: Which cytokines promote eosinophil activation?
A: IL-5 is the main eosinophil activating cytokine.
Innate Immunity
1. Q: What are the main types of pattern recognition receptors (PRRs) and
their ligands?
A: Toll-like receptors (TLRs) recognize PAMPs like LPS; NOD-like
receptors (NLRs) detect intracellular bacterial components; RIG-I-like
receptors detect viral RNA; C-type lectin receptors bind fungal
carbohydrates.
2. Q: How does the inflammasome contribute to innate immunity?
A: It activates caspase-1, leading to cleavage of pro-IL-1β and pro-IL-18
into their active forms, promoting inflammation.
3. Q: Describe the role of dendritic cells in bridging innate and adaptive
immunity.
A: Dendritic cells capture antigens, mature, migrate to lymph nodes, and
present antigen via MHC molecules to naïve T cells, initiating adaptive
responses.
4. Q: What is the function of natural killer (NK) cells?
A: NK cells recognize and kill virus-infected or tumor cells via missing-
self recognition and produce cytokines like IFN-γ to activate
macrophages.
5. Q: How do complement pathways get activated?
A: Classical pathway: antibody-antigen complexes; lectin pathway:
mannose-binding lectin binding pathogens; alternative pathway:
spontaneous hydrolysis of C3.
Adaptive Immunity
6. Q: What is somatic hypermutation and where does it occur?
A: Somatic hypermutation introduces point mutations in the variable
regions of immunoglobulin genes in germinal centers to increase
antibody affinity.
7. Q: Explain the difference between MHC class I and class II molecules.
A: MHC I presents endogenous peptides to CD8+ T cells; MHC II
presents exogenous peptides to CD4+ T cells.
, 8. Q: What cytokines drive differentiation of naïve CD4+ T cells into Th1
cells?
A: IL-12 and IFN-γ promote Th1 differentiation.
9. Q: How do regulatory T cells (Tregs) suppress immune responses?
A: Tregs suppress via cytokines like IL-10 and TGF-β and by cell
contact-dependent mechanisms involving CTLA-4.
10.Q: What is the role of activation-induced cytidine deaminase (AID)?
A: AID is critical for class switch recombination and somatic
hypermutation in B cells.
Immunogenetics and Antigen Recognition
11.Q: Describe V(D)J recombination.
A: It’s the somatic recombination process of variable (V), diversity (D),
and joining (J) gene segments in B and T cell receptor genes generating
receptor diversity.
12.Q: What enzyme initiates V(D)J recombination?
A: RAG1 and RAG2 recombinase enzymes.
13.Q: Explain positive and negative selection in the thymus.
A: Positive selection ensures T cells recognize self-MHC; negative
selection deletes strongly self-reactive T cells.
14.Q: How does cross-presentation differ from regular antigen presentation?
A: Cross-presentation is when exogenous antigens are presented on MHC
class I molecules to CD8+ T cells.
15.Q: What molecular interaction stabilizes the immunological synapse?
A: LFA-1 (on T cells) binding to ICAM-1 (on APCs).
Cytokines and Signaling
16.Q: What are the main functions of IL-2?
A: IL-2 promotes T cell proliferation, survival, and differentiation.
17.Q: Describe JAK-STAT signaling in immune cells.
A: Cytokine binding activates JAK kinases, which phosphorylate STAT
transcription factors that dimerize and regulate gene expression.
18.Q: Which cytokines promote eosinophil activation?
A: IL-5 is the main eosinophil activating cytokine.
