NCLEX : Immunoglobulins

Study concepts, example questions & explanations for NCLEX

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 : Immunoglobulins

Which of the following is the primary immunoglobulin secreted into the intestinal lining and mucus membranes of the respiratory tract?

Possible Answers:

IgE

IgA

IgM

IgG

Correct answer:

IgA

Explanation:

IgA, primarily in its secretory form (sIgA), is the most abundant immunoglobulin in the lining of the gastrointestinal tract and in the mucus membranes of the respiratory tract. It is also present in the urogenital tract, in tears, in saliva, and in breast milk. All of the other immunoglobulins may be present in mucus membranes, depending on the presence of active infection or allergy, but none is as abundant in secretions as IgA. IgE is primarily involved in binding allergens and inducing the allergic response via release of histamine. IgM is expressed on the surface of B cells and is the first immunoglobulin to fight pathogens at the site of infection/injury. IgG are the most abundant antibody throughout the body and play the largest role in fighting pathogens. IgG can cross the placenta and thus confer passive immunity to the fetus. 

Example Question #2 : Immunoglobulins

The presence of which of the following cytomegalovirus (CMV) antibodies would suggest an active CMV infection?

Possible Answers:

CMV IgE

CMV IgG

CMV IgD

CMV IgM

Correct answer:

CMV IgM

Explanation:

The presence of CMV IgM would suggest an active cytomegalovirus infection, as IgM is the immunoglobulin released during the initial, active infection with a pathogen. The presence of IgG would suggest a past infection, where IgG specific to the virus would be present as part of adaptive immunity (ready to respond to the virus should the host ever be re-exposed). IgE is not formed when an individual contracts CMV, as IgE is produced in response to allergens rather than pathogens (except parasites). The function of IgD is thought to be related to the allergic response by regulating basophils and mast cells.

Example Question #3 : Immunoglobulins

Which of the following is the only immunoglobulin capable of crossing the placenta and conferring passive immunity to a fetus?

Possible Answers:

IgM

IgE

IgG

IgA

Correct answer:

IgG

Explanation:

The only immunoglobulin that has been shown to be able to cross the placenta is IgG. This is important in that it confers short term immunity to the fetus that continues into the first few months of the infant's life. Note that it is common to give Rh-negative anti-Rh IgG injections at about 28 weeks gestation; a booster may also be given at about 34 weeks gestation.

Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: