Exam 1: Set 1 Flashcards
A previously healthy 8-year-old boy is infected with an upper respiratory tract virus for the first time. During the first few hours of infection, which one of the following events occurs?
a. The adaptive immune system responds rapidly to the virus and keeps the viral infection under control.
b. The innate immune system responds rapidly to the viral infection and keeps the viral infection under control.
c. Passive immunity mediated by maternal antibodies limits the spread of infection.
d. B and T lymphocytes recognize the virus and stimulate the innate immune response.
e. The virus causes malignant transformation of respiratory mucosal epithelial cells, and the malignant cells are recognized by the adaptive immune system.
b. The innate immune system responds rapidly to the viral infection and keeps the viral infection under control.
Which of the following is a unique property of the adaptive immune system?
a. Highly diverse repertoire of specificities for antigens
b. Self-nonself discrimination
c. Recognition of microbial structures by both cell-associated and soluble receptors
d. Protection against viral infections
e. Responses that have the same kinetics and magnitude on repeated exposure to the same microbe
a. Highly diverse repertoire of specificities for antigens
A standard treatment of animal bite victims, when there is a possibility that the animal was infected with the rabies virus, is administration of human immunoglobulin preparations containing anti–rabies virus antibodies. Which type of immunity would be established by this treatment?
a. Active humoral immunity
b. Passive humoral immunity
c. Active cell-mediated immunity
d. Passive cell-mediated immunity
e. Innate immunity
b. Passive humoral immunity
At 15 months of age, a child received a measles-mumps-rubella vaccine (MMR). At age 22, she is living with a family in Mexico that has not been vaccinated and she is exposed to measles. Despite the exposure, she does not become infected. Which of the following properties of the adaptive immune system is best illustrated by this scenario?
a. Specificity
b. Diversity
c. Specialization
d. Memory
e. Nonreactivity to self
d. Memory
The two major functional classes of effector T lymphocytes are:
a. Helper T lymphocytes and cytotoxic T lymphocytes
b. Natural killer cells and cytotoxic T lymphocytes
c. Memory T cells and effector T cells
d. Helper cells and antigen-presenting cells
e. Cytotoxic T lymphocytes and target cells
a. Helper T lymphocytes and cytotoxic T lymphocytes
Which of the following best describes clonal expansion in adaptive immune responses?
a. Increased number of different lymphocyte clones, each clone specific for a different antigen during the course of an infection
b. Increased number of different lymphocyte clones, each clone specific for a different antigen during development of the immune system, before exposure to antigen
c. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte due to nonspecific stimuli from the innate immune system
d. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte stimulated by a single antigen
e. Increased size of the lymphocytes of a single clone due to antigen-induced activation of the cells
d. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte stimulated by a single antigen
Which of the following statements about the innate immune system is NOT true?
a. Innate immunity is present in all multicellular organisms, including plants and insects.
b. Deficiencies in innate immunity markedly increase host susceptibility to infection, even in the setting of an intact adaptive immune response.
c. Innate immunity is better suited for eliminating virulent, resistant microbes than is adaptive immunity.
d. The innate immune response can be divided into recognition, activation, and effector phases.
e. The innate immune response against microbes influences the type of adaptive immune response that develops.
c. Innate immunity is better suited for eliminating virulent, resistant microbes than is adaptive immunity.
Toll-like receptors (TLRs) are a family of homologous receptors expressed on many cell types and are involved in innate immune responses. Ten different mammalian TLRs have been identified, and several ligands for many of these receptors are known. Which of the following is a TLR ligand?
a. Single-stranded RNA
b. Transfer RNA
c. Double-stranded DNA
d. Unmethylated CpG DNA
e. Heterochromatin
d. Unmethylated CpG DNA
The signaling pathways triggered by Toll-like receptors typically result in activation of which of the following pairs of transcription factors?
a. NFAT and T-bet
b. AP-1 and GATA-3
c. Fos and STAT-6
d. NFB and AP-1
e. Lck and Jun
d. NFB and AP-1
Which of the following is a receptor on macrophages that is specific for a structure produced by bacteria but not by mammalian cells?
a. Scavenger receptor AI
b. Fc receptor
c. Complement receptor
d. Mannose receptor
e. ICAM-1
d. Mannose receptor
