Exam 3_PQ 3

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.

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.