Cell Mediated Immunity and Effector Responses in Medical Microbiology

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What is the primary role of cell-mediated immunity?

To recognize and eliminate tumor cells
To protect against extracellular antigens
To detect and eliminate cells that harbor intracellular pathogens (correct)
To neutralize antigens

Which type of immune response is responsible for eliminating foreign cells and altered self-cells?

Adaptive immunity
Cell-mediated immunity (correct)
Humoral immunity
Innate immunity

What is the function of CD4+ effector T cells in cell-mediated immunity?

To mediate delayed type hypersensitivity reactions (correct)
To recognize and eliminate tumor cells
To produce antibodies
To activate macrophages

What is the purpose of co-stimulation in T cell activation?

To provide a second signal for T cell activation (B) Signup and view all the answers

What is the role of adhesion molecules in T cell responses?

To stabilize T cell-APC binding (A) Signup and view all the answers

What is the function of CD28 on T cells?

To bind to B7 on APCs (B) Signup and view all the answers

What is the result of the interaction between CD40L on T cells and CD40 on APCs?

No direct effect on T cell activation (D) Signup and view all the answers

What is the purpose of clonal expansion in T cell responses?

To increase the number of antigen-specific T cells (A) Signup and view all the answers

What is the function of cytokines in T cell responses?

To organize and support cell-mediated immunity (D) Signup and view all the answers

What is the difference between humoral and cell-mediated immunity?

Humoral immunity protects against extracellular antigens, while cell-mediated immunity protects against intracellular antigens (B) Signup and view all the answers

Which of the following molecules is NOT involved in target cell destruction by CTLs?

IFN-gamma (C) Signup and view all the answers

What is the primary function of TH1 cells in immunity?

Macrophage activation (A) Signup and view all the answers

Which of the following is a characteristic of naive T cytotoxic cells?

Incapability of carrying out cytotoxic activity (C) Signup and view all the answers

What is the primary mechanism by which adjuvants enhance T cell-dependent immune responses in vaccines?

By inducing the expression of costimulators on APCs and stimulating cytokine secretion (A) Signup and view all the answers

What is the role of CD40L-CD40 interaction in T cell activation?

To activate T cells by making APCs better at stimulating T cells (A) Signup and view all the answers

What is the primary role of CD40 ligand in T-cell effector functions?

B-cell activation (B) Signup and view all the answers

During which phase of the CTL-mediated immune response do effector CTLs recognize and eliminate target cells?

Phase 2 (C) Signup and view all the answers

What is the function of CTLA-4 and PD-1 in T cell activation?

To inhibit T cell activation by terminating responses (C) Signup and view all the answers

What is the primary mechanism of cross-presentation by dendritic cells?

Ingestion of infected cells and presentation of microbial antigens to CD8+ T cells and CD4+ helper T cells (D) Signup and view all the answers

Which of the following cytokines is secreted by TH1 cells to promote macrophage activation?

IFN-gamma (A) Signup and view all the answers

What is the primary requirement for the activation of CD8+ T cells?

Recognition of class I MHC-associated peptides and costimulation (C) Signup and view all the answers

What is the role of antigen-presenting cells (APCs) in the activation of CD8+ T cells?

To ingest infected cells and present microbial antigens to CD8+ T cells and CD4+ helper T cells (C) Signup and view all the answers

What type of immune response is dominated by the production of immunoglobulin E (IgE) antibodies and the activation of eosinophils?

Helminthic infections (B) Signup and view all the answers

Which type of CD4+ T cells produces interferon-γ (IFN-γ) as its signature cytokine?

Th1 cells (D) Signup and view all the answers

What is the primary function of Th17 cells in the immune response?

Stimulation of neutrophil recruitment (D) Signup and view all the answers

Which type of T cells recognizes class I MHC-peptide complexes on the surface of infected cells?

CD8+ T cells (C) Signup and view all the answers

What is the purpose of co-stimulatory signals in T cell activation?

To provide a second signal necessary for T cell activation (B) Signup and view all the answers

Which type of immune response is characterized by the production of IL-4, IL-5, and IL-13?

Th2 response (C) Signup and view all the answers

What is the primary function of CD8+ cytotoxic T lymphocytes (CTLs)?

To kill infected cells (A) Signup and view all the answers

What is the role of IL-12 and IFN-γ in the differentiation of CD4+ T cells?

To induce Th1 cell differentiation (C) Signup and view all the answers

What is the primary function of IL-2 in the generation of cytotoxic T cells?

Proliferation and differentiation of antigen-activated naïve CTL into effector CTLs (C) Signup and view all the answers

Which of the following is NOT a requirement for the generation of CTLs from naïve CTLs?

Interaction with IL-10 (B) Signup and view all the answers

What is the purpose of CD45RO in effector T cells?

To enhance TCR signal transduction (B) Signup and view all the answers

What is the primary function of LFA-1 in the effector phase of a CTL-mediated response?

Formation of a conjugate with target cells (D) Signup and view all the answers

What is the primary function of granzymes and perforin in CD8+ CTLs?

To kill infected cells (C) Signup and view all the answers

What is the result of the interaction between FasL and Fas on the surface of target cells?

Induction of apoptosis in target cells (D) Signup and view all the answers

In IL-2 knockout mice, what is the effect on CTL-mediated cytotoxicity?

It is abolished (D) Signup and view all the answers

What is the purpose of the temporary high-avidity state of LFA-1 after antigen-mediated activation?

To facilitate dissociation of CTL from target cells (C) Signup and view all the answers