Exam 2 - patho

IL-2

T cell proliferation; regulatory T cell survival

What cellular source does IL-2 do?

Activated T cells

Interferon-y (IFN-y)

Activation of macrophages

What is the cellular source of Interferon-y (IFN-y)?

CD4+ and CD8+ T cell, natural killer cells

IL-4

B cell switching to IgE

What is the cellular source of IL-4?

CD4+ T cells, mast cells

IL-5

Activation of eosinophils

What is the cellular source of IL-5?

CD+4 T cells, mast cells, innate lymphoid cells

IL-17

Stimulation of acute inflammation

What is the cellular source for IL-17?

CD4+ T cells, other cells

Il-22

Maintenance of epithelia barrier functions

What is the cellular source for Il-22?

CD4+ T cells, NK cells, innate lymphoid cells

TGF-Beta

Inhibition of T cell activation ; differentiation of regulatory T cells

What is the cellular source of TGF-Beta

CD4+ T cells; many other cell types

A patient with a chronic helminth infection shows high levels of IL-4 and IL-5. Which T cell subset is likely activated?

TH2

A deficiency in AIRE leads to autoimmunity due to a failure in:

Expression of tissue-specific antigens in the thymus

A new therapy increases the expression of CTLA-4 on T cells. What is the most likely immune outcome?

Decreased T cell co-stimulation

T/F : Positive selection ensures that T cells can recognize self-MHC molecules

True

T / F : Naïve CD8+ T cells can directly kill infected cells without any co-stimulation

False

T / F : Regulatory T cells contribute to peripheral tolerance and prevent autoimmunity.

True

Which of the following are features of central T cell tolerance?

1. Occurs in the thymus

2. Involves negative selection

3. May lead to Treg cell development

A mutation in RAG-1 prevents recombination of antigen receptor genes. What outcome would you expect?

Absence of mature B and T cells

A virus infects host cells and inhibits MHC class I expression. Which immune response is most a\ected?

Activation of CD8+ cytotoxic T cells

A patient lacks IL-2 receptors. What is the most likely immune defect?

Deficient regulatory T cell function

A therapeutic agent that blocks PD-1 would most likely:

Enhance anti-tumor immunity

A patient with a defect in Fas or FasL will most likely develop:

Autoimmune lympohopliferative syndrome

T / F :CTLs induce apoptosis in target cells primarily through perforin and granzymes

True

T / F: T follicular helper cells promote IgE production

False

T / F : IL-10 is a cytokine that promotes inflammation.

False

T / F : TH1 cells activate macrophages via CD40-CD40L and IFN-γ

True

Which mechanism are used by CTLs to kill infected cells?

1. Granzyme B

2. Perforin

3. Fas-FasL interaction

TH1

macrophage activation

TH2

Eosinophil recruitment

Th17

Neutrophil recruitment

Treg

Immune suppression

CD28

Co-stimulatory receptor on T cells

CTLA-4

Inhibits T cell activation

B7

ligand found on APCS

PD-1

inhibitory receptor that limits responses

Which factors are important for the development of TH17 cells?

1. IL-6

2. IL-1

3. IL-23

4. TGF-Beta1

Which are mechanisms of peripheral T cell tolerance ?

1. Anergy

2. Deletion via apoptosis

3. Suppression by regulatory T cells

A researcher knocks out IL-12 in mice. What would you expect in terms of helper T cell differentiation?

Decreased TH1 cells

Which T cell subset is most likely responsible for maintaining epithelial barrier function in the gut?

TH17

A cancer immunotherapy blocks TGF-β signaling. Which T cell function is most likely affected?

Differentiation of regulatory T cells

A patient has high IL-10 and TGF-β expression in mucosal tissues. What is the most likely immune outcome?

Tolerance to commensal microbes

T / F : CTLA-4 competes with CD28 for B7 binding

True

T / F : Positive selection eliminates T cells that strongly recognize self-antigens

False

T / F : IL-2 is involved in both T cell proliferation and regulatory T cell survival

True

T / F : PD-1 is expressed on naïve T cells

False

Type 1 Diabetes

CTL-mediated β-cell destruction

rheumatoid arthritis

TH1/TH17-driven joint inflammation

Autoimmune lymphoproliferative syndrome (ALPS)

Fas/FasL mutation

Allergic asthma

Overactive TH2 response

zeta chain

ITAM-bearing signaling subunit

CD28

Co-stimulatory receptor

TCR

Antigen recognition

CD3

Signal transduction

A vaccine stimulates the generation of T cells that respond rapidly upon re-exposure to antigen but do not home to lymph nodes. These are most likely:

Effector memory T cells

A CD8+ T cell kills an infected cell by releasing granzymes and perforin. Which of the following best describes the mechanism?

Creation of membrane pores and caspase activation

Which cytokine is most critical for the long-term survival of memory T cells?

IL-7

Which pair of molecules is used by CD8+ cytotoxic T lymphocytes (CTLs) to kill infected target cells?

FasL and perforin

An individual is repeatedly infected with the same virus, but experiences milder symptoms each time. This is best explained by:

Memory T cell response

A patient has asthma with elevated eosinophils and IL-5 production. Which type of hypersensitivity is involved?

Type I

Which immune component is most responsible for acute transplant rejection?

Alloreactive T cells

A 35-year-old female develops hives and wheezing minutes after a bee sting. This is most likely due to:

IgE- mediated mast cell degranulation

What distinguishes chronic transplant rejection from acute rejection?

Fibrosis and vascular thickening over months to years

Which of the following therapies blocks negative co-stimulation to enhance T cell activation against tumors?

Anti-CTLA-4 antibody

A child has hemolytic anemia due to antibodies against red blood cell antigens. Which hypersensitivity type is this?

Type II

A kidney transplant recipient develops signs of rejection 4 days after surgery. Biopsy reveals T cell infiltration. What type of rejection is this?

Acute

A patient with metastatic melanoma is treated with anti-PD-1 therapy. What is the goal of this treatment?

Reactivate tumor-specific T cells

Contact dermatitis from poison ivy is best classified as which hypersensitivity type?

Type IV

Which of the following hypersensitivity reactions involves immune complex deposition in tissues such as the kidneys or joints?

Type III

T / F : Type I hypersensitivity requires prior sensitization to the allergen

True

T / F : CTLs are the main immune cells responsible for eliminating tumor cells

True

Which of the following are examples of Type I hypersensitivity?

1. Anaphylaxis

2. Allergic rhinitis

3. Asthma

A bone marrow biopsy shows developing B cells expressing a heavy chain paired with surrogate light chains (VpreB and λ5). What stage of B cell development is most likely occurring?

Pre-B cell stage

A patient has a mutation in the RAG-1 gene, which prevents functional recombination of B and T cell receptor genes. What is the most likely immunological consequence?

Failure to produce mature B ad T lymphocytes

What checkpoint follows successful expression of the mature B cell receptor (BCR)?

Negative selection against self-reactive BCRs

Which of the following contributes to junctional diversity during somatic recombination?

Addition of nucleotides by TDT

What happens to a developing B cell that fails to express a functional surrogate BCR?

It is eliminated via apoptosis

What is the primary function of the surrogate B cell receptor expressed during early B cell development?

To ensure functional heavy chain rearrangement and signal further development

Which enzyme complex is responsible for initiating somatic recombination of antigen receptor genes in developing lymphocytes?

VDJ recombinase complex (including RAG-1 and RAG-2)

An inhibitory receptor (e.g., CTLA-4) is blocked on T cells in a mouse. Which of the following will occur?

I. The mouse will be predisposed to autoimmune reactions.

II. The mouse will have a decreased likelihood of functionally inactivating its T cells.

III. The mouse will have increased tolerance to Ags.

I and II

Which of the following is produced and displayed by an infected cell to induce a cytotoxic T cell response?

class I MHC + microbial peptide

Which of the following is true about regulatory T cells? Tregs:

depend upon Foxp3 expression for their function

Which of the following is/are likely to contribute to the development of autoimmunity?

I. expression of self-antigen in the generative lymph organs

II. cross-reactivity of pathogen and self-antigens

III. tissue injury that releases normally hidden self-antigens

II and III

Which of the following is TRUE about an immature T cell?

It is double positive and expresses a TCR

Which of the category of hypersensitivity is Ig-E-mediated?

Type I

When a T cell receptor binds its antigen, which of the following is responsible for signal transduction via ITAMs?

CD3

Which is NOT TRUE about tumor antigens? Tumor antigens may be:

Normally expressed cellular proteins

Cytotoxic T cells produce __________, which induce(s) caspase activation.

granzymes

Which of the following could be the result of expsosure to a tolerogenic antigen?

I. anergy

II. suppression

III. apoptosis

I, II, III

Th1 cells secrete cytokines that:

activate macrophages

Which of the following provide(s) evidence that there are immune responses against tumor cells?

I. Lymphocytes are found around tumors.

II. Tumor transplants are rejected.

III. Immunocompetent individuals have increased incidence of tumors.

I and II

Enzymes that transfer phosphate groups to a protein are known as:

protein kinases

Which of the following is recognized by helper T cells?

cells that display foreign peptides on mHC class II

Th1 cells will help macrophages eliminate which of the following?

bacteria that resist lysosomal degradation

Which of the following is true about tolerogenic Ags?

Many are expressed in high concentrations in the generative organs

Which of the category of hypersensitivity reactions involves a T-cell response?

Type IV

In what manner does a type III hypersensitivity reaction differ from a type II hypersensitivity reaction?

The antigens involved in a type III reaction are not bound to a cell's surface, while those involved in a type II reaction are bound to the surface.