Deck 18: Applications of Immune Responses

Question 1

A new parent asks you which vaccines the CDC recommends for a 2-month-old infant. Based on the latest CDC's recommended immunization schedules found online, what is your answer?

Answer 1

Vaccination   is an immunization procedure in which a person develops immunity, particularly against a specific pathogen. Vaccines contain live attenuated or killed organisms that are injected to the person in a series or one time in the lifetime.
The vaccines recommended by Centers for Disease Control and prevention (CDC) for a two year infant include,
1. Rota virus (RV) vaccine - 1 st dose of the 3 dose series
2. DTaP (Diphtheria, tetanus, pertussis) vaccine - 1 st dose of the 4 dose series
3. Haemophilus influenza type b vaccine (Hib) vaccine - 1 st dose of the 4 dose series
4. Pneumococcal conjugate vaccine - 1 st dose of the 4 dose series
5. Inactivated polio virus - 1 st dose of the 3 dose series

Question 2

An ELISA test is used to screen patient specimens for HIV. A positive ELISA test is confirmed by a Western blot test. Why not the other way around, with the ELISA second?

Answer 2

Enzyme-linked immunosorbent assay (ELISA) is an immunological assay. If the ELISA is designed to detect an antibody (produced against a particular antigen), it is called "indirect ELISA."
Positive result with indirect ELISA (enzyme linked immune sorbent assay) occurs only if seroconversion occurs. Seroconversion is a stage of conversion of a negative test result for a particular antibody to a positive test result for the same antibody. Means, if the patient is recently infected and produce only a few number of antibodies, the result will be indeterminate. This result obtained by ELISA is non-specific because it uses a well that contains a mixture of pathogens (antigens). It is likely to produce false positive results, so the result is confirmed by another sensitive laboratory test.
In contrast, western blot technique is more specific because it clearly shows the presence of antigen recognized by the antibody by a discrete protein band. Western blot technique provides more specific results than the ELISA. However, ELISA is commonly used over Western blot technique because performing western blot is a time consuming process, and it requires technical expertise. In contrast to western blot, ELISA can be done at the bedside, or "point-of-care (POC)" testing.

Question 3

Active immunity occurs naturally in response to infections, and artificially in response to vaccination. Passive immunity occurs naturally from maternal antibodies transferred during pregnancy and breast feeding, and artificially through administration of immune serum globulin or hyperimmune globulin.
How is naturally acquired active immunity different from artificially acquired active immunity?

Answer 3

Naturally acquired active immunity occurs when a person is unintentionally exposed to an infectious agent or pathogen and then develops an immunity against that pathogen that lasts a lifetime. For example, if a child contracts chickenpox, their body will develop antibodies, which will combat the chickenpox pathogen for the rest of their life.
Artificially acquired active immunity results when a person receives an injected vaccine that stimulates the body to produce antibodies against the injected pathogen (antigen). Although the MMR ( M easles, M umps, R ubella) vaccination confers active immunity against these three pathogens, two injections are recommended. This is necessary because between 2%-5% of people do not develop measles immunity after the first injection.

Question 4

Which is an example of immunization that elicits active immunity?

A) Giving antibodies against diphtheria
B) Immune globulin injections to prevent hepatitis
C) Inactivated polio vaccine
D) Rabies immune globulin
E) Tetanus immune globulin

Question 5

How is immune globulin different from hyperimmune globulin?

Question 6

In tests to determine if a patient has measles, the laboratory looks for IgM. Why would finding IgM be more significant than finding IgG?

Question 7

Staphylococcus aureus makes a protein called protein A, which binds to the Fc region of antibody molecules from a wide variety of species. How could protein A be exploited in immunoassays?

Question 8

Active immunity occurs naturally in response to infections, and artificially in response to vaccination. Passive immunity occurs naturally from maternal antibodies transferred during pregnancy and breast feeding, and artificially through administration of immune serum globulin or hyperimmune globulin.
What is antitoxin?

Question 9

Breast feeding provides which of the following to an infant?

A) Artificial active immunity
B) Artificial passive immunity
C) Natural active immunity
D) Natural passive immunity

Question 10

Describe two advantages of an attenuated vaccine over an inactivated one.

Question 11

Active immunity occurs naturally in response to infections, and artificially in response to vaccination. Passive immunity occurs naturally from maternal antibodies transferred during pregnancy and breast feeding, and artificially through administration of immune serum globulin or hyperimmune globulin.
If an unvaccinated person suffers a deep puncture wound that puts him or her at risk for tetanus, why would TIG be advised rather than simply vaccinating the individual?

Question 12

Vaccines ideally should be all of the following, except

A) effective in protecting against the disease.
B) inexpensive.
C) stable.
D) living.
E) easily administered.

Question 13

Describe two advantages of an inactivated vaccine over an attenuated one.

Question 14

An attenuated vaccine is a weakened form of the pathogen. An inactivated vaccine is unable to replicate but retains the immunogenicity of the pathogen or toxin; examples include killed microorganisms, inactivated viruses, and fractions of the agents, including toxoids. Routine childhood immunizations have prevented millions of cases of disease and many deaths during the past decades. Many experimental vaccines are under study or in clinical trials.
What is the difference between an attenuated and inactivated vaccine?

Question 15

Severely immunosuppressed people should not receive the measles vaccine. Based on this information, the vaccine is

A) an inactivated whole agent.
B) a toxoid.
C) a subunit vaccine.
D) a genetically engineered vaccine against hepatitis B.
E) an attenuated vaccine.

Question 16

What is herd immunity?

Question 17

An attenuated vaccine is a weakened form of the pathogen. An inactivated vaccine is unable to replicate but retains the immunogenicity of the pathogen or toxin; examples include killed microorganisms, inactivated viruses, and fractions of the agents, including toxoids. Routine childhood immunizations have prevented millions of cases of disease and many deaths during the past decades. Many experimental vaccines are under study or in clinical trials.
Childhood diseases such as measles and mumps are rare now, so why is it important for children to be immunized against them?

Question 18

All of the following are attenuated vaccines except

A) chickenpox.
B) mumps.
C) rubella.
D) pertussis.
E) yellow fever.

Question 19

Describe how both active and passive immunization can be used to combat tetanus.

Question 20

An attenuated vaccine is a weakened form of the pathogen. An inactivated vaccine is unable to replicate but retains the immunogenicity of the pathogen or toxin; examples include killed microorganisms, inactivated viruses, and fractions of the agents, including toxoids. Routine childhood immunizations have prevented millions of cases of disease and many deaths during the past decades. Many experimental vaccines are under study or in clinical trials.
What would be a primary advantage of using an attenuated agent for a vaccine rather than just an antigen from that agent?

Question 21

An important subunit vaccine that is widely used is the

A) pertussis vaccine.
B) oral polio vaccine.
C) inactivated polio vaccine.
D) measles vaccine.
E) mumps vaccine.

Question 22

Why are humanized monoclonal antibodies better for therapy than the original versions?

Question 23

Immunoassays are used to detect or quantify given antigens or antibodies in a sample. The sample may be serially diluted to determine the antibody titer. Antibodies used in immunoassays can be either polyclonal or monoclonal.
What is the significance of a rise in titer of specific antibodies in serum samples taken at different times?

Question 24

In quantifying antibodies in a patient's serum

A) total protein in the serum is measured.
B) the antibody is usually measured in grams per ml.
C) the serum is serially diluted.
D) both antigen and antibody are diluted.
E) the titer refers to the amount of antigen added.

Question 25

What is the purpose of anti-human IgG antibodies in immunological testing?

Question 26

Immunoassays are used to detect or quantify given antigens or antibodies in a sample. The sample may be serially diluted to determine the antibody titer. Antibodies used in immunoassays can be either polyclonal or monoclonal.
How are polyclonal antibodies different from monoclonal antibodies?

Question 27

Which of the following about immunological testing is false?

A) Polyclonal antibody preparations recognize multiple epitopes.
B) Monoclonal antibodies recognize a single epitope.
C) Serum and plasma can both be tested for antibodies.
D) The direct ELISA uses anti-human IgG antibodies.
E) A rise in specific antibody titer indicates an active infection.

Question 28

What is an advantage of the fluorescent antibody test over an ELISA?

Question 29

Immunoassays are used to detect or quantify given antigens or antibodies in a sample. The sample may be serially diluted to determine the antibody titer. Antibodies used in immunoassays can be either polyclonal or monoclonal.
Would antibodies produced by a patient in response to infection be monoclonal, or polyclonal?

Question 30

All of the following are matching pairs except

A) ELISA-radioactive label.
B) fluorescence-activated cell sorter-flow cytometry.
C) fluorescent antibody test-microscopy.
D) Western blot-gel electrophoresis.

Question 31

Is blood typing an example of a precipitation reaction or an agglutination reaction?

Question 32

Antibodies labeled with a detectable marker can be used to identify an antigen (direct test) or to detect a patient's antibodies to a known antigen (indirect test). Examples of methods that use labeled antibodies include ELISA, Western blotting, fluorescence antibody tests, and fluorescence-activated cell sorters. Agglutination and precipitation reactions both depend on formation of visible antigen-antibody complexes.
Why is the ELISA used so commonly relative to the Western blot?

Question 33

Which of the following would be most useful for screening thousands of specimens for antibodies that indicate a certain disease?

A) Western blot
B) Fluorescent antibody
C) ELISA
D) All of the above
E) None of the above

Question 34

In a precipitation reaction, what is meant by "optimal proportions"?

Question 35

Antibodies labeled with a detectable marker can be used to identify an antigen (direct test) or to detect a patient's antibodies to a known antigen (indirect test). Examples of methods that use labeled antibodies include ELISA, Western blotting, fluorescence antibody tests, and fluorescence-activated cell sorters. Agglutination and precipitation reactions both depend on formation of visible antigen-antibody complexes.
How is a direct agglutination test different from a passive agglutination test?

Question 36

Antibodies labeled with a detectable marker can be used to identify an antigen (direct test) or to detect a patient's antibodies to a known antigen (indirect test). Examples of methods that use labeled antibodies include ELISA, Western blotting, fluorescence antibody tests, and fluorescence-activated cell sorters. Agglutination and precipitation reactions both depend on formation of visible antigen-antibody complexes.
Why is a false-positive more significant in HIV testing of patients than in screening donated blood for transfusions?