Chapter 18

Question 1

Edward Jenner:

Answer 1

-developed the modern practice of vaccination when he inoculated people with cowpox virus to protect them against smallpox

Principles of vaccination:
-herd immunity results when most of the population is immune to a disease

Question 2

Types of Vaccinations:

Answer 2

• live attenuated vaccines consist of attenuated (weakened) microorganisms, attneuated virus vaccines generally provide lifelong immunity
• inactivated vaccines consist of killed bacteria or viruses
• subunit vaccines consist of antigenic fragments of a microorganism; these include toxoids, virus-like particles, and polysaccarides
• conjugated vaccines combine the desired antigen with a protein that boosts the immune response
• nucleic acid (DNA) vaccines cause the recipient to make the antigenic protein
• recombinant vector vaccines are avirulent viruses or bacteria genetically modified to produce a desired antigen

Question 3

Vaccine Production, Delivery Methods, and Formulations

Answer 3

• viruses for vaccines may be grown in animals, cell cultures, or chick embroys
• recombinant vaccines and nucleic acid vaccines do not need to be grown in cells or animals
• genetically modified plants may someday provide edible vaccines
• dry skin patch vaccines don’t need refrigeration
• oral administration and combining several vaccines would eliminate the number of injections required for vaccinations
• adjuvants improve the effectiveness of some antigens
• vaccines are the safest and most effective means of controlling infectious diseases

Question 4

Diagnostic Immunology:

Answer 4

• many tests based on the interactions of antibodies and antigens have been developed to determine the presence of antibodies or antigens in a patient
• the sensitivity of a diagnostic test is determined by the percentage of positive samples it correctly detects and its specificity is determined by the percentage of negative results it gibes when the specimens are negative
• direct tests are used to identify specific microorganisms
• indirect tests are used to demonstrate the presence of antibody in serum
• diseases can be diagnosed by a rising titer or seroconversion (from no antibodies to the presence of antibodies)

Question 5

Use of Monoclonal Antibodies:

Answer 5

• hybridomas are produced in the laboratory by fusing a cancerous B-cell with an antibody-secreting plasma cell
• a hybridoma cell culture produces large quantitites of the plasma cell’s antibodies, called minoclonal antibodies
• monoclonal antibodies are used to treat disease and in diagnostic serological tests

Question 6

Precipitation Reactions

Answer 6

• the interaction of soluble antigens with IgG or IgM antibodies leads to precipitation reactions
• precipitation reactions depend on the formation of lattices and occur best when antigen and antibody are present in optimal proportions
• immunodiffusion procedures are precipitation reactions carried out in an agar gel medium
• immunielectrophoresis combines electrophoresis with immunodiffusion for the analysis of serum proteins

Question 7

Aggulation Reactions:

Answer 7

• the interaction of particulate antigens (cells that carry antigens) with antibodies leads to aggulation reactions
• diseases may be diagnosed by combining the patient’s serum with a known antigen
• antibodies cause visible aggulation of soluble antigens affixed to latex spheres in indirect or passive aggulation tests
• hemaggulation reactions involve aggulation reactions using red blood cells. Hemaggulation reactions are used in blood typing, the diagnosis of certain diseases, and the identification of viruses

Question 8

Neutralization Reactions:

Answer 8

• in neutralization reactions, the harmful effects of a bacterial exotoxin or virus are eliminated by a specific antibody
• an antitoxin is an antibody produced in response to a bacterial exotoxin or toxoid that neutraluzes the exotoxin
• in a virus neutralization test, the presence of antibodies against a virus can be detected by the antibodies’ ability to prevent cytopathic effects of viruses in cell cultures
• in viral hemaggulation inhibition tests, antibodies against certain viruses can be detected by their ability to interfere with viral hemaggulation

Question 9

Complement-Fixation Reactions

Answer 9

-complement fixation reactions are serological tests based on the depletion of a fixed amount of complement in the presence of an antigen-antibody reaction

Question 10

Fluroscent-Antibody Techniques

Answer 10

• flurescent-anitbody techniques use antibodies labeled with flurescent dyes
• a floresence-activated cell sorter can be used to detect and count cells labeled with fluroscent antibodies

Question 11

Enzyme-Linked Immunosobent Assay (ELISA)

Answer 11

• ELISA techniques use antibodies linked to an enzyme
• antigen-antibody reactions are detected by enzyme activity. If the indivator enzyme is present in the test well, an antigen-antibody reaction has occured

Question 12

Western Blotting (Immunoblotting)

Answer 12

-serum antibodies separated by electrophoresis are identified with an enzyme-linked antibody

Question 13

The Future of Diagnostic and Therapeutic Immunology

Answer 13

the use of monoclonal antibodies and nucleic acid amplifcatoion tests will make new diagnostic tests possible