Exam 16: The Immune System: Adaptive Immunity

MHC molecules are required for

CASE HISTORY Luke,a 24-year-old mechanic from Egypt Beach,Massachusetts,was feeling run-down.Over the past month he had not been eating much and was always tired,and he recently noticed pain just under his right rib cage.His urine had recently turned the color of tea,and his wife noticed that the whites of his eyes were taking on a yellowish tinge.Luke finally went to the doctor,who suspected Luke had cirrhosis,a liver disease.This preliminary diagnosis was based on Luke's symptoms.Luke's abdominal pain was located over the liver,and the color of his urine and the jaundice evident in his eyes all pointed toward liver disease.Luke did not drink alcohol and had never left the country,but when questioned,Luke admitted to taking intravenous drugs.The doctor suspected hepatitis and ordered a series of blood tests to check for the presence of liver enzymes,antihepatitis antibodies,and hepatitis DNA or RNA in his blood.The tests revealed a high level of hepatitis B viral DNA.Luke had hepatitis B disease. How can cellular immunity,which normally protects the body against known viral and other intracellular pathogens,be harmful to Luke,given his diagnosis? Consider how T cells recognize and respond to cells displaying foreign antigen.

Which of the following would you expect to elicit the largest production of antibodies?

Which of the following statements correctly describes the molecules that elicit an immune response?

Describe the function of the major histocompatibility complex (MHC).

Class switching is the process in which

Why is it important for T cells to weakly recognize self MHC proteins while strong recognition is problematic?

The process illustrated in this figure is best described as

One health risk associated with excessive cytokine release is the chance of

The immunoglobulin superfamily of proteins includes

How do the structure and function of the F(ab)and Fc regions of an antibody differ?

Helper T cells display the surface antigen ________.

Which of the following cell types is considered a "nonprofessional" antigen-presenting cell?

How would you expect an injection of killed or attenuated Salmonella typhi,the causative agent of typhoid fever,to protect an individual?

CASE HISTORY Nathan was a ten-month-old male who had suffered much in his short life.Since birth he had experienced recurrent serious extracellular bacterial infections,all of which were resolved by antibiotic treatment.On Christmas Day,Nathan's mother discovered he had another high fever and a nonproductive cough (no mucus).He was also having trouble breathing.Fearing one more serious infection,Nathan's mother rushed him to the hospital.An X-ray showed the lung infiltrate with the appearance of ground glass.A tube was placed through Nathan's nose and into his lung,and a solution was used to wash out deep-lung contents for microscopic examination (bronchoalveolar lavage).The fluid yielded microscopic organisms.Nathan was hospitalized with pneumonia caused by Pneumocystis jirovecii,a yeastlike fungus.Although most of us have been infected with this organism,our immune systems almost always prevent disease.Finding the disease in Nathan suggested a serious immune dysfunction.An immunological workup revealed mild neutropenia (lower than normal numbers of neutrophils)but normal numbers of T and B cells,normal levels of complement,and normal complement activity.However,Nathan's blood exhibited exceptionally high levels of IgM but very low IgG and IgA levels.The physician suspected a specific defect in Nathan's T cells. Based on his findings regarding antibody production,which defect do you think Nathan's doctor suspects is causing Nathan's immunodeficiency?

Describe the two-step molecular process required to activate TH0 cells.

Small molecules that do not elicit an immune response unless they are attached to immunogens are referred to as ________.

Antigen bound by the molecule shown would be recognized by ________ cells.

The second signal required for T_C activation is

Rebecca developed measles as a young child.As a teenager,she is reexposed to the measles virus during an outbreak at her high school.Explain the immune response that will most likely prevent Rebecca from experiencing any signs or symptoms of measles.