Chapter 18: Practical Applications of Immunology

Who developed the modern practice of vaccination?

Edward Jenner, by inoculating people with cowpox virus to protect against smallpox.

What is herd immunity?

Herd immunity occurs when most of a population is immune to a disease, reducing its spread.

What are attenuated vaccines?

Vaccines that use weakened (attenuated) microorganisms; they generally provide lifelong immunity.

What are inactivated vaccines?

Vaccines that consist of killed bacteria or viruses.

What are subunit vaccines?

accines made from antigenic fragments of a microorganism, including toxoids, virus-like particles, polysaccharides, and conjugated vaccines.

What is a conjugated vaccine?

A vaccine that combines the desired antigen with a protein to boost the immune response.

How do nucleic acid vaccines work?

DNA and mRNA vaccines cause the recipient’s cells to produce the antigenic protein.

What are recombinant vector vaccines?

Vaccines that contain avirulent viruses or bacteria genetically modified to produce a desired antigen.

Where can viruses for vaccines be grown?

In animals, cell cultures, or chick embryos.

How are recombinant and nucleic acid vaccines produced?

In bacterial, yeast, or animal cell cultures.

What is a potential future method for producing vaccines?

Genetically modified plants may provide edible vaccines.

What is an advantage of dry skin patch vaccines?

They don’t need refrigeration.

How can the number of injections required for vaccinations be reduced?

Through oral administration or combining several vaccines.

What is the role of adjuvants in vaccines?

They improve the effectiveness of some antigens.

What is considered the safest and most effective means of controlling infectious diseases?

Vaccines.

What are many diagnostic tests in immunology based on?

The interactions of antibodies and antigens to detect the presence of antibodies or antigens in a patient.

How is the sensitivity of a diagnostic test defined?

By the percentage of positive samples it correctly detects.

How is the specificity of a diagnostic test defined?

By the percentage of negative results it gives when the specimens are actually negative.

What are direct tests used for?

To identify specific microorganisms.

What are indirect tests used for?

To demonstrate the presence of antibodies in serum.

How can diseases be diagnosed using antibody levels?

By observing a rising titer or seroconversion (from no antibodies to the presence of antibodies).

What is a hybridoma?

A laboratory-produced cell formed by fusing a cancerous B cell with an antibody-secreting plasma cell.

what do hybridoma cell cultures produce?

Large quantities of the plasma cell’s antibodies, called monoclonal antibodies.

What are monoclonal antibodies used for?

Treating diseases and in diagnostic tests.

What leads to precipitation reactions in immunology?

the interaction of soluble antigens with IgG or IgM antibodies.

on what do precipitation reactions depend?

the formation of lattices, and they occur best when antigen and antibody are in optimal proportions.

What is immunodiffusion?

A precipitation reaction carried out in an agar gel medium.

What is immunoelectrophoresis?

A technique that combines electrophoresis with immunodiffusion for the analysis of serum proteins.

What leads to agglutination reactions?

The interaction of particulate antigens (cells carrying antigens) with antibodies.

How can diseases be diagnosed using agglutination?

by combining a patient’s serum with a known antigen to observe visible clumping.

what is indirect or passive agglutination?

a test where antibodies cause visible agglutination of soluble antigens affixed to latex spheres.

what are hemagglutination reactions?

Agglutination reactions using red blood cells, used for blood typing, diagnosing certain diseases, and identifying viruses.

What happens in neutralization reactions?

The harmful effects of a bacterial exotoxin or virus are eliminated by a specific antibody.

What is an antitoxin?

An antibody produced in response to a bacterial exotoxin or toxoid that neutralizes the exotoxin.

How does a virus neutralization test detect antibodies?

By observing the antibodies’ ability to prevent cytopathic effects of viruses in cell cultures.

What is the principle behind viral hemagglutination inhibition tests?

Antibodies against certain viruses are detected by their ability to interfere with viral hemagglutination.

What are complement-fixation reactions?

Serological tests based on the depletion of a fixed amount of complement in the presence of an antigen–antibody reaction.

What are fluorescent-antibody techniques?

Techniques that use antibodies labeled with fluorescent dyes to detect specific antigens.

What is a fluorescence flow cytometer used for?

To detect and count cells labeled with fluorescent antibodies.

What is an ELISA?

An Enzyme-Linked Immunosorbent Assay that uses antibodies linked to an enzyme to detect antigen–antibody reactions by enzyme activity.

how does ELISA indicate antigen–antibody binding?

if the indicator enzyme is present in the test well, it shows that antigen–antibody binding has occurred.

What is Western blotting (immunoblotting)?

A technique where proteins separated by electrophoresis are identified using an enzyme-linked antibody.

How will monoclonal antibodies impact the future of immunology?

They will enable the development of new diagnostic tests and therapies.