Exam 3_PQ 3

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Questions and Answers

What is the primary role of allergen immunotherapy in treating Type I hypersensitivity?

To enhance the production of IgE antibodies

To inhibit the Th1 response

To induce a systemic IgA response

To promote tolerance to specific allergens (correct)

Which immunoassay method is commonly used to detect IgE levels in patients with Type I hypersensitivity?

Flow cytometry

Western blotting

ELISA-based immunoassays (correct)

Radiography

Which type of allergens are typically targeted in allergen-specific immunotherapy?

Inhalant allergens and food allergens (correct)

Pathogen-associated allergens

Genetically modified organisms

Only contact allergens

What mechanism do regulatory T cells primarily use to modulate allergic responses in Type I hypersensitivity?

Suppressing effector T cell functions Signup and view all the answers

In the context of allergen-specific responses, what is the role of Th2 cells during the sensitization phase?

To secrete IL-4 and IL-13 that induce IgE production Signup and view all the answers

What is a common clinical symptom of allergic asthma?

Gasping for breath Signup and view all the answers

Which of the following treatments is classified as a fast-acting bronchodilator?

Albuterol Signup and view all the answers

What role do corticosteroids play in asthma treatment?

Reduce inflammation and prevent late-phase response Signup and view all the answers

Which monoclonal antibody is targeted against IL-4Rα?

Dupilumab Signup and view all the answers

What is the primary action of anti-IL-5 therapies in asthma treatment?

Reducing eosinophil levels Signup and view all the answers

Which of the following describes a common feature of allergen immunotherapy?

Long-term tolerance development Signup and view all the answers

In allergic asthma, which cell type is primarily activated in response to allergens?

Mast cells Signup and view all the answers

Which type of allergen response is typically mediated by IgE antibodies?

Localized anaphylaxis Signup and view all the answers

Which treatment is NOT commonly used for atopic dermatitis?

Epinephrine Signup and view all the answers

Which clinical manifestation is associated with atopic urticaria (hives)?

Vasodilation and edema Signup and view all the answers

What is a common trigger for systemic anaphylaxis?

Ingested foods Signup and view all the answers

What is a key feature of food allergies in children?

Activation of mast cells in the GI tract Signup and view all the answers

Which mechanism is involved in the localized reaction seen in atopic urticaria?

Degranulation of skin mast cells Signup and view all the answers

What is the main goal of Allergen Immunotherapy (AIT)?

To alter the immune response to allergens Signup and view all the answers

What is the significance of regulatory T cells (Treg) in AIT?

They suppress inflammatory immune cells Signup and view all the answers

Elimination diets are used primarily to identify which aspect of food allergies?

The responsible allergens Signup and view all the answers

Which of these would most likely NOT be a result of systemic anaphylaxis?

Skin lesions Signup and view all the answers

Which type of administration method represents subcutaneous immunotherapy?

Injection under the skin Signup and view all the answers

What role do mast cells play in allergic reactions?

They release mediators that lead to inflammation Signup and view all the answers

What is the expected change in antibody production during AIT?

Decreased IgE and increased IgG Signup and view all the answers

Which immune cells are suppressed by regulatory T cells during allergen immunotherapy?

Mast cells and basophils Signup and view all the answers

Which option correctly describes a key characteristic of Type I hypersensitivity?

IgE-mediated response involving mast cell activation Signup and view all the answers

What is the initial treatment step recommended for systemic anaphylaxis?

Administer epinephrine Signup and view all the answers

What is the role of tolerogenic dendritic cells (DCs) induced by AIT?

To induce immune tolerance to allergens Signup and view all the answers

Which of the following best describes the SLIT method of AIT?

Allergen dropped under the tongue Signup and view all the answers

In which type of hypersensitivity reaction does AIT primarily function?

Type I hypersensitivity Signup and view all the answers

What are the targets of IgE antibodies in the case of Type I hypersensitivity?

Environmental allergens like pollen Signup and view all the answers

What is the primary outcome of allergen immunotherapy related to tissue response?

Reduced mucus production Signup and view all the answers

What is the purpose of conducting skin prick tests in allergy testing?

To identify the presence of allergens through wheal and flare reactions Signup and view all the answers

Which of the following statements accurately describes ImmunoCAP®?

It utilizes a chemiluminescent assay for measuring allergen-specific IgE. Signup and view all the answers

What is a potential risk associated with skin testing for allergies?

The possibility of sensitizing an individual to new allergens Signup and view all the answers

Which adjunctive treatment is commonly used for allergic reactions?

Antihistamines Signup and view all the answers

What is the primary function of vasoconstriction in the context of allergic reactions?

Elevate heart rate and blood pressure Signup and view all the answers

Which method allows for the simultaneous testing of multiple allergens?

Skin prick test Signup and view all the answers

What is a known limitation of late-phase responses in allergy testing?

They can lead to tissue damage after initial sensitization. Signup and view all the answers

In allergen immunotherapy, which type of allergens is primarily targeted?

Specific allergens known to trigger IgE responses Signup and view all the answers

Which of the following is NOT a typical method used for adjunctive treatments in allergy management?

Immunoassays Signup and view all the answers

What role do regulatory T cells play in allergic reactions?

They help suppress the allergic response. Signup and view all the answers

What are the appropriate antibodies used in the HIV western blot technique?

Anti-HIV antibodies; Patient serum antibodies Signup and view all the answers

Which of the following best describes the concept of sensitivity in a diagnostic assay?

The ability to correctly identify those with the disease Signup and view all the answers

In the context of quantitative PCR (qPCR), which CT value indicates the highest viral load?

The lowest CT value Signup and view all the answers

Which patient showed a strong positive result in the latex agglutination test for strep throat infection?

Patients 1, 3, 4 and 5 Signup and view all the answers

What does a titer of 32 indicate in a hemagglutination assay?

The last well that showed agglutination was well number 32. Signup and view all the answers

For the rapid diagnostic assay identifying exposure to infected reindeer, what is the approximate sensitivity based on the provided data?

65% Signup and view all the answers

Which detection mechanism is appropriate to identify anti-EGF antibodies in an indirect ELISA?

enzyme-labeled anti-human IgG Signup and view all the answers

What blood type is indicated if all tubes show identical results when mixed with a patient's blood?

Type O Signup and view all the answers

What is the main goal of immunoblotting in detecting HIV?

To confirm the presence of antibodies against HIV Signup and view all the answers

What role do precipitin lines play in precipitation reactions?

They confirm the binding of antibodies to soluble antigens. Signup and view all the answers

In which scenario would precipitation be favored over agglutination?

When detecting small particles in a fluid Signup and view all the answers

What technique is used primarily to confirm a positive HIV test result?

Immunoblotting Signup and view all the answers

Which statement is true about the differences between precipitation and agglutination reactions?

Both reactions can be performed using monoclonal antibodies. Signup and view all the answers

Why is secondary antibody labeling important in immunoblotting?

To amplify the signal for detection Signup and view all the answers

In which assay would you most likely utilize a fluorescently-labeled secondary antibody?

Immunofluorescence Assay (IFA) Signup and view all the answers

How is the specificity of a diagnostic test generally defined?

The percentage of true negatives identified Signup and view all the answers

What is one key difference between hemagglutination and latex agglutination assays?

Hemagglutination detects blood group antibodies, latex agglutination detects bacterial infections. Signup and view all the answers

Which statement is correct regarding the equivalence zone in precipitation reactions?

It represents optimal antibody-antigen interaction levels. Signup and view all the answers

In developing assays, which factor is crucial for ensuring optimal sensitivity?

Optimal pH and temperature during the reaction Signup and view all the answers

Study Notes

Allergic Asthma

Activation of mast cells in the lower respiratory tract, causing bronchoconstriction and increased mucus secretion
Symptoms include coughing, wheezing, open-mouth breathing, and/or gasping for breath
Treatment includes biologics, bronchodilators, and corticosteroids

Monoclonal Antibodies

Anti-IL-4Rα (Dupilumab): Targets IL-4 and IL-13 receptors to inhibit their action, blocking the Th2 pathway
Anti-IgE (Omalizumab): Binds to free IgE in the bloodstream, preventing it from binding to mast cells and initiating the allergic response
Anti-IL-5 (Reslizumab and Mepolizumab): Targets IL-5, a cytokine that stimulates the production and activation of eosinophils
Anti-IL-5Rα (Benralizumab): Binds to the IL-5 receptor on eosinophils, inhibiting their activation and function

Type I Hypersensitivity

Involves an exaggerated IgE-mediated response to allergens
Atopy refers to the predisposition to develop Type I hypersensitivity reactions, often with a genetic component
The hygiene hypothesis suggests that increased hygiene practices can contribute to a higher prevalence of atopic disorders
Two distinct phases: sensitization and effector

Sensitization Phase

Initial allergen exposure triggers a Th2 response
Effector Th2 cells secrete IL-4 and IL-13, which induce B cells to switch to IgE production
IgE binds to FcεRs on mast cells, priming them for future allergen encounters

Effector Phase

Upon re-exposure to the allergen, the allergen binds to IgE on mast cells, initiating the release of pre-formed and newly synthesized mediators
These mediators contribute to the symptoms of allergic reactions, including bronchoconstriction, increased mucus production, and inflammation
The release of mediators causes rapid onset of symptoms, classifying this as an immediate hypersensitivity reaction

Western Blot for HIV Detection

HIV Western Blot is a technique used to confirm the presence of HIV antibodies in a patient's serum.
HIV proteins are separated by gel electrophoresis and transferred to a membrane.
The membrane is incubated with primary antibodies (1o), which are patient serum antibodies, followed by labeled secondary antibodies (2o).
The secondary antibodies are anti-human IgG antibodies, which bind to the primary antibodies.

Sensitivity of a Rapid Diagnostic Assay

A new rapid diagnostic assay was developed to detect "Reindeeritis" in elves.
The assay was tested on 1000 elves, with a confirmatory PCR conducted to determine the disease status.
The sensitivity of the assay is calculated as the number of true positives divided by the total number of individuals with the disease.
The sensitivity of this assay is approximately 90%.

Quantitative PCR (qPCR) and Viral Load

qPCR was used to quantify the amount of a novel DNA virus in six patients suspected of infection.
The CT value (cycle threshold) represents the number of cycles required for the fluorescent signal to cross a threshold, indicating the amount of viral DNA present.
A lower CT value indicates a higher viral load.
Patient A has the highest viral load because their amplification plot has the lowest CT value.
The approximate CT value for Patient B is 28.

Latex Agglutination Test for Strep Throat

A latex agglutination test was performed on five patients suspected of having strep throat.
The test involves mixing bacterial antigens extracted from throat swabs with antistreptococcal antigens conjugated to blue latex beads.
Agglutination (clumping) of the beads indicates a positive test result.
Patients 1, 3, 4, and 5 have strong positive test results as evidenced by clearly visible agglutination in their samples.

Molecular Assays for Detecting Bacteria

IFA (Immunofluorescence Assay): Detects patient antibodies by using a fluorescently-labeled secondary antibody.
Latex Agglutination: A reaction between an insoluble antigen and a soluble antibody, visualized on a test card.
Double Immunodiffusion: Detects patient antibodies by using an agar plate.

Hemagglutination Assay and Titer

A hemagglutination assay is used to detect antibodies that agglutinate red blood cells.
A titer of 32 indicates that the last well showing agglutination had antibody diluted 1/32.

Blood Typing

Blood typing identifies the antigens present on red blood cells using antibodies specific to each antigen.
If a patient's blood does not agglutinate with any of the antibodies (Type A, Type B, or buffer), the patient is most likely blood type O.
Blood type O does not express the A or B antigens.

Indirect ELISA

An indirect ELISA is used to detect antibodies in a patient's serum.
The microtiter plate is coated with the target antigen (e.g., epidermal growth factor).
Patient serum containing potential antibodies is added.
Enzyme-labeled anti-human IgG is added to detect any bound patient antibodies directed against the target antigen.

Precipitation and Agglutination Reactions

Precipitation reactions involve the formation of a visible precipitate when soluble antigens bind to soluble antibodies.
Agglutination reactions involve the clumping of particles (e.g., red blood cells or latex beads) when they are bound by antibodies.
Equivalence zone: The optimal concentration of antigen and antibody for precipitation reactions.
Monoclonal antibodies can be used in both precipitation and agglutination assays.
Agglutination reactions can be used to detect either antigens or antibodies by modifying the assay.

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Description

Test your knowledge on allergic asthma and the role of monoclonal antibodies in its treatment. This quiz covers the mechanisms of mast cell activation, treatment options, and the characteristics of Type I hypersensitivity. Perfect for students in medical or health-related fields.