Question 1

A 6-year-old female is diagnosed with a bacterial infection of the respiratory system. Which of the following will most likely try to fight the antigen?

Accepted Answer

Antibodies are proteins produced by the immune system to identify and neutralize foreign objects like bacteria and viruses. In a bacterial infection, antibodies will most likely try to fight the antigen.

Question 2

If a person is given antigen X and is later given antigen Y, a(n)_____ response to antigen Y will result.

Accepted Answer

C

Question 3

Which of the following cells is responsible for presenting the antigen to the immune cells during clonal selection?

Accepted Answer

Antigen-processing cells, such as dendritic cells, macrophages, and B cells, are responsible for presenting the antigen to the immune cells during clonal selection. T cells and B cells are both types of lymphocytes involved in the immune response, but they do not present the antigen to other cells during clonal selection.

Question 4

A 25-year-old female has sexual relations with her boyfriend. Later she is told that the boyfriend is infected with Neisseria gonorrhoeae. Testing reveals that she does not have the disease. How is it possible that she did not contract the disease?

Accepted Answer

Antibodies produced by the woman may have covered the sites of attachment for Neisseria gonorrhoeae, preventing the bacteria from infecting her. It is also possible that the woman's immune system was able to successfully fight off the infection before it fully established itself.

Question 5

The predominant antibody of a typical primary immune response is:

Accepted Answer

During a primary immune response, IgM antibodies are the first to be produced in significant amounts. IgG antibodies become more predominant during the secondary immune response. Therefore, option B (IgM) is the best choice for this question.

Question 6

The most abundant class of antibody in the serum is:

Accepted Answer

IgG is the most abundant class of antibody in the serum. It accounts for about 75% of all antibodies, and is involved in long-term protection against bacteria and viruses.

Question 7

The primary role of secretory IgA is to prevent infections in:

Accepted Answer

Secretory IgA plays an important role in preventing infections in mucous membranes, where it can bind to and neutralize pathogens before they are able to invade the body's tissues. It is found in high concentrations in saliva, tears, and other bodily fluids that come into contact with these membranes. It is not involved in preventing infections in blood vessels, kidneys, or lungs.

Question 8

Both B and T cells are originally derived from cells of the:

Accepted Answer

Both B cells and T cells originate from hematopoietic stem cells in the bone marrow.

Question 9

At a 12-month well-baby visit, the mother reports that the child has never been ill. She proudly reports that the baby was breastfed since birth. The nurse tells her that breastfeeding is beneficial because the dominant antibody in breast milk acts by functioning as an antigen receptor:

Accepted Answer

The dominant antibody in breast milk is secretory IgA (sIgA), which functions as an antigen receptor in mucosal membranes, such as the intestines, respiratory tract, and urogenital tract. sIgA helps to prevent attachment and colonization of pathogenic microorganisms in these areas.

Question 10

An experiment is carried out to characterize newly discovered immunoglobulins. Specificity of the immunoglobulin could be determined by studying the:

Accepted Answer

The specificity of an immunoglobulin is determined by the complementary-determining region (CDR) of the variable domains in the H and L chains. The C region of the H and L chains are important for determining the functional properties of the antibody, but not for specificity. The framework regions are also important for the three-dimensional structure of the antibody, but do not directly contribute to specificity.

Question 11

Which of the following characteristics is shared by both the secretory and systemic immune systems?

Accepted Answer

Neutralization following antigen-antibody binding is a shared characteristic between the secretory and systemic immune systems. Both systems use antibodies to bind to and neutralize pathogens, leading to their destruction or removal from the body. The other options (A, C, and D) are not shared characteristics between the two immune systems.

Question 12

A molecule is isolated from the human body and studied. It is found to react with antibodies on B cells. Further testing reveals that the molecule is large and chemically diverse. Which of the following would best describe the molecule?

Accepted Answer

An antigen is a molecule that can be recognized by antibodies, often large and chemically diverse, and can react with antibodies on B cells.

Question 13

A 10-year-old male is stung by a bee while playing in the yard. He experiences a severe allergic reaction and has to go to the ER. This reaction is the result of:

Accepted Answer

A severe allergic reaction to a bee sting is caused by the release of histamine and other chemicals by mast cells and basophils, which are triggered by an immune response involving IgE antibodies. Toxoids are inactivated toxins used for vaccination against infectious diseases. IgA is an antibody that plays a role in mucosal immunity. IgM is the first antibody produced in response to an infection. None of these are directly involved in an allergic reaction to a bee sting.

Question 14

The immunoglobulin that crosses the placenta confers _____ immunity to the fetus.

Accepted Answer

The immunoglobulin that crosses the placenta from the mother to the fetus is IgG, which provides passive acquired immunity to the fetus. This means that the fetus does not produce the antibodies itself, but rather receives pre-formed antibodies from the mother.

Question 15

A 20-year-old female is applying for nursing school and is required to be tested for immunity against several illnesses. Testing that looks at which of the following would be the best to determine immunity?

Accepted Answer

Titer testing is the best method for determining immunity as it measures the level of antibodies in the blood to a specific pathogen. It provides a quantitative measurement of the individual's level of protection against the disease. Neutralization, agglutination, and precipitation tests are all types of serological tests, but they are not as specific as titer testing for immunity.

Question 16

A 3-year-old male is diagnosed with autoimmune-induced type 1 diabetes. Which of the following therapies may help prevent worsening of the disease?

Accepted Answer

The answer of A 3-year-old male is diagnosed with autoimmune-induced...

Question 17

A 23-year-old pregnant female visits her physician for her final prenatal checkup. The physician determines that the fetus has developed an infection in utero. Which of the following would be increased in the fetus at birth?

Accepted Answer

IgM is the first antibody produced in response to an infection and can cross the placenta to provide passive immunity to the fetus. Therefore, if a fetus has an infection in utero, it is likely that IgM levels will be increased at birth. IgG also crosses the placenta and provides passive immunity, but it is produced later in the immune response and therefore would not be increased in the fetus at birth if there was an in utero infection. IgA and IgD do not typically cross the placenta and therefore would not be increased in the fetus at birth in response to an in utero infection.

Question 18

A 16-year-old male is bitten by a rabid dog while jogging in the park. Upon admission to the ER, he is given _____ to prevent infection.

Accepted Answer

Immunoglobulins, specifically rabies immunoglobulins, are given to prevent infection after exposure to the rabies virus. They provide immediate protection while the body's own immune system ramps up to produce its own antibodies. Cytotoxic T cells and helper T cells are parts of the body's immune response but do not provide immediate protection.

Question 19

Which portion of the antibody is responsible for activating the inflammatory systems?

Accepted Answer

The Fc portion of the antibody is responsible for activating the inflammatory systems by binding to Fc receptors on inflammatory cells, such as macrophages and neutrophils, and triggering the release of inflammatory mediators.

Question 20

Which of the following characteristics increases an antigen's ability to be immunogenic?

Accepted Answer

Combining with carrier molecules increases the size and complexity of the antigen, making it more recognizable to the immune system and therefore more immunogenic. Small size (A) and minimal chemical complexity (B) may make an antigen less immunogenic. Extremely high concentrations (D) may actually have the opposite effect and lead to immune tolerance.

Quiz 6: Adaptive Immunity