Immunology: Antibody-Antigen Interactions

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What is the primary application of direct agglutination tests?

To diagnose infectious diseases (correct)
To detect antibodies to bacterial infections
To detect blood group ABO and Rhesus compatibility
To detect viral infections

What is the advantage of using carrier particles in passive agglutination tests?

Increases the sensitivity of the test
Enhances the specificity of the test
Detects antibodies to viruses
Provides consistency, uniformity, and stability (correct)

What is the result of agglutination in a direct agglutination test?

Positive result (correct)
Invalid result
Inconclusive result
Negative result

What type of agglutination test is used to detect antibodies to viruses such as rubella and HIV-1/HIV-2?

Passive agglutination (C) Signup and view all the answers

What is the characteristic of the antigen in direct agglutination?

An intrinsic component of the particle (B) Signup and view all the answers

What is the result of no agglutination in a direct agglutination test?

Negative result (B) Signup and view all the answers

What is the primary event occurring during the sensitization phase?

Antibody molecules attaching to their corresponding antigenic sites (B) Signup and view all the answers

What is the minimum number of antibody molecules required to sensitize red cells before they form enough cross-bridges to agglutinate?

Several hundred (C) Signup and view all the answers

How does the location and concentration of antigenic determinants on the particle affect agglutination?

The larger the number of antigen sites, the more antibody will attach to the cells, thus increasing the chances of cross-bridges forming (A) Signup and view all the answers

Why can IgM agglutinate cells more easily than IgG?

Because IgM has ten antigen combining sites, whereas IgG has two (B) Signup and view all the answers

What is the role of antibody isotype in agglutination?

It affects the ability of antibodies to bridge the distance between red cells (D) Signup and view all the answers

What is the primary factor that affects the stabilization of antigen-antibody complexes?

The formation of cross-links between antibody molecules (D) Signup and view all the answers

What is the term for the antibody that interacts with antigen on the surface of particles?

Agglutinin (C) Signup and view all the answers

What is the primary phase of agglutination reaction?

Sensitization (D) Signup and view all the answers

What is the term for the antigen on the surface of particles that react with the antibody to produce agglutination?

Agglutinogen (D) Signup and view all the answers

What is the result of the interaction between an antibody and a particulate antigen?

Agglutination (D) Signup and view all the answers

What is the advantage of agglutination techniques in the clinical laboratory?

Simple and inexpensive (B) Signup and view all the answers

What is the term for the reaction that involves red blood cells?

Hemagglutination (A) Signup and view all the answers

What is the purpose of testing for antibody in agglutination reaction?

To identify the antibody in a patient sample (B) Signup and view all the answers

What is the form of agglutination that involves latex particles?

Latex agglutination (C) Signup and view all the answers

What is the term for the visible manifestation of the agglutination reaction?

Clumping (C) Signup and view all the answers

What is the purpose of the primary phase of agglutination?

To react with a single antigenic determinant on the surface of the antigen (C) Signup and view all the answers