Question 1

Which of the following tests is not correctly matched to its positive reaction?

Accepted Answer

All the tests are correctly matched to their positive reactions: Complement fixation test's positive result is indicated by no hemolysis, ELISA relies on an enzyme-substrate reaction to produce a detectable signal, Neutralization test's positive outcome is shown by no tissue or animal death, and Hemagglutination is characterized by the clumping of red blood cells.

Question 2

Purified protein from B. pertussis is a(n)

Accepted Answer

Subunit vaccines include only the parts of the virus or bacterium that best stimulate the immune system. In this case, a purified protein from B. pertussis (whooping cough bacterium) would be used to create a subunit vaccine, focusing on specific antigens without introducing the whole pathogen.

Question 3

Which is the third step in a direct ELISA test?

Accepted Answer

B

Question 4

If a patient shows the presence of antibodies against diphtheria toxin, this indicates all of the following except

Accepted Answer

The presence of antibodies against diphtheria toxin indicates that the patient has either been vaccinated, had the disease and recovered, or received antibodies through a transfusion. It does not indicate that the patient was merely near someone who had the disease, as antibodies are not transferred through casual contact.

Question 5

What type of vaccine is live measles virus?

Accepted Answer

The live measles virus vaccine is an example of an attenuated whole-agent vaccine. This means the vaccine contains a version of the living virus that has been weakened so it doesn't cause disease in people with healthy immune systems.

Question 6

A vaccine against HIV proteins made by vaccinia virus is a(n)

Accepted Answer

Subunit vaccines include only the parts of the virus or bacterium that best stimulate the immune system. In this case, the vaccine against HIV proteins made by vaccinia virus includes only specific proteins of the HIV virus, not the whole virus, making it a subunit vaccine.

Question 7

A reaction between an antibody and soluble antigen- forming lattices is called a(n)

Accepted Answer

Precipitation reactions involve the combination of soluble antigens with soluble antibodies to form large, insoluble complexes that precipitate out of solution, forming lattices.

Question 8

An indirect version of which test using antihuman globulin may be used to detect patient's antibodies against Treponema pallidum?

Accepted Answer

The indirect immunofluorescence test, specifically the Fluorescent Treponemal Antibody Absorption (FTA-ABS) test, is used to detect antibodies against Treponema pallidum, the bacterium that causes syphilis. This test is highly specific and is often used to confirm a syphilis infection after an initial positive screening test.

Question 9

Antibodies for serological testing can be obtained from all of the following except

Accepted Answer

Viral cultures are used to grow and isolate viruses, not to produce antibodies. Antibodies are produced by the immune system of humans or animals in response to an antigen, or they can be produced artificially as monoclonal antibodies.

Question 10

Dead Bordetella pertussis can be used in a(n)

Accepted Answer

Inactivated whole-agent vaccines are made from microorganisms (like bacteria or viruses) that have been killed or inactivated but are still capable of eliciting an immune response. Dead Bordetella pertussis fits this category, as the bacteria are killed and used to immunize against whooping cough.

Question 11

Which of the following is a pregnancy test used to find the fetal hormone HCG in a woman's urine using anti- HCG and latex spheres?

Accepted Answer

The correct answer is B) Passive agglutination reaction. This method involves the use of latex spheres coated with anti-HCG antibodies. When a woman's urine, which may contain the hormone HCG if she is pregnant, is added to the test, the HCG binds to the anti-HCG on the latex spheres, causing them to agglutinate. This agglutination is an indication of a positive pregnancy test.

Question 12

Live polio virus can be used in a(n)

Accepted Answer

Live polio virus is used in attenuated whole-agent vaccines, where the virus is weakened but still alive, allowing the immune system to build a defense without causing the disease.

Question 13

Which of the following is most useful in determining the presence of AIDS antibodies?

Accepted Answer

Indirect ELISA is most useful in determining the presence of AIDS antibodies because it is specifically designed to detect the presence of antibodies in a sample by using an antigen-coated surface to capture the antibody, which is then detected using a secondary antibody that is enzyme-linked. This method is highly sensitive and specific for detecting HIV antibodies in blood samples.

Question 14

Situation 18.1
In an immunodiffusion test to diagnose histoplasmosis, patient's serum is placed in a well in an agar plate. In apositive test, a precipitate forms as the serum diffuses from the well and meets material diffusing from a second well
-The immunodiffusion test described in Situation 18.1 is

Accepted Answer

The immunodiffusion test described is a precipitation reaction, where soluble antigens and antibodies interact in a gel medium to form a visible precipitate, indicating a positive test for the presence of antibodies against the pathogen in question, in this case, Histoplasma.

Question 15

All of the following are disadvantages of a live virus vaccine except

Accepted Answer

Live virus vaccines typically induce a strong and long-lasting immune response, often superior to that of inactivated viruses, because they mimic a natural infection more closely.

Question 16

A reaction between antibody and particulate antigen is called a(n)

Accepted Answer

Agglutination reactions involve the clumping of particles, such as cells, when specific antibodies bind to antigens on the surface of those particles. This is distinct from reactions involving soluble antigens (precipitation) or the use of complement, fluorescence, or neutralization mechanisms.

Question 17

Situation 18.1
In an immunodiffusion test to diagnose histoplasmosis, patient's serum is placed in a well in an agar plate. In apositive test, a precipitate forms as the serum diffuses from the well and meets material diffusing from a second well
-In Situation 18.1, what is in the second well?

Accepted Answer

In an immunodiffusion test for diagnosing histoplasmosis, the second well contains a fungal antigen specific to Histoplasma capsulatum. When the patient's serum, containing antibodies, diffuses and meets the fungal antigen, a precipitate forms indicating a positive test.

Question 18

Which of the following is a test to determine the presence of soluble antigens in patient's saliva?

Accepted Answer

The answer of Which of the following is a test...

Question 19

To detect botulinum toxin in food, suspect food is injected into two guinea pigs. The guinea pig that was vaccinated against botulism survives, while the one that was not vaccinated dies. This is an example of

Accepted Answer

This is an example of neutralization, where the vaccinated guinea pig's immune system neutralizes the botulinum toxin, preventing it from causing harm, while the non-vaccinated guinea pig lacks this protection and dies. Neutralization tests involve the interaction of an antigen with its antibody to neutralize the effects of toxins or viruses.

Question 20

The circumsporozoite antigen of Plasmodium can be used for all of the following except to

Accepted Answer

The circumsporozoite antigen of Plasmodium is used in vaccine development to prevent infection (D), can be targeted by monoclonal antibodies for diagnostic or therapeutic purposes (B), and may help in reducing the risk of recurring infections by inducing some level of immunity (A). However, it is not used to cure people who are already infected with Plasmodium, as current treatments for malaria involve antimalarial drugs rather than vaccines or antibodies targeting the circumsporozoite protein.

Quiz 18: Practical Applications of Immunology