Immuno Set 3 (Innate Immunity) 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.
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
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 IRF B. GATA-3 and NFkB C. STAT-6 and NFkB D. NFkB and IRF E. IRF and STAT3
D. NFkB and IRF
Macrophages express a broad range of plasma membrane receptors that mediate their interactions with natural and altered-self components of the host as well as a range of microorganisms. Recognition is followed by surface changes, uptake, signaling, and altered gene expression, contributing to homeostasis, host defense, innate effector mechanisms, and the induction of acquired immunity. 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
Phagocytosis is a central event in the innate immune responses that are triggered by recognition of PAMPs on the surface of pathogens by PRRs receptors on the membrane of phagocytes. Particularly, complement-mediated phagocytosis is accomplished by specific recognition of bound complement components by the corresponding complement receptors on the phagocytes. Which of the following is critical for phagocytosis?
A. C4b B. C2a C. C2b D. C3a E. C3b
E. C3b
The complement system is a part of the immune system that enhances (complements) the ability of immune cells to clear microbes and damaged cells, promotes inflammation, and attacks the pathogen’s cell membrane. Complement is required for which of the following reactions?
A. lysis of erythrocytes by lecithinase B. NK-mediated lysis of tumor cells C. generation of ROS and NO D. lysis of bacteria E. All of the above.
D. lysis of bacteria
- A 76-year-old man is diagnosed with Escherichia coli septicemia. The initial immune response to E. coli (gram-negative bacteria) will include which of the following?
A. binding by LPS-binding proteins and delivery to receptors on macrophages.
B. formation of specific somatically generated receptors to bind E. coli.
C. generation and secretion of specific antibodies to recognize E. coli.
D. production of E. coli-specific cytokines by lymphocytes.
E. stimulation of killer activation receptors on NK cells.
A. binding by LPS-binding proteins and delivery to receptors on macrophages.
Johnny is a 1-month-old healthy child who has not, as yet, received any childhood immunizations. He presents with his first episode of otitis media (middle ear infection) that is successfully treated with a 3-week course of antibiotics. Which one of the following immune components contributed the most to his clearing the infectious agent during the first few days of his infection?
A. Antigen receptors on his B lymphocytes
B. Toll-like receptors on his neutrophils
C. Cytokines that promoted antibody formation
D. T cell responses to bacterial antigens
E. Memory B cells
B. Toll-like receptors on his neutrophils
A 23-year-old male presents with fever, headache, and vomiting. Laboratory investigations revealed leukocytosis, elevated levels of C-reactive protein, and normal levels of blood immunoglobulins. Patient was successfully treated with intravenous antibiotics and fully recovered 10 days later. Detailed investigations revealed a defect in IL-1 receptor-associated kinase (IRAK)-dependent cellular signaling associated with his TLR4 receptor. Which one of the following most likely caused infection in this patient?
A. Retroviruses, such as HIV-1 B. Fungi that cause vaginal yeast infections C. Gram-negative bacteria D. Gastrointestinal viruses E. Insect-borne parasites
C. Gram-negative bacteria
