Exam 1: Set 2 Flashcards
Complement system is an important effector component of the innate immune system. More than 30 plasma proteins undergo a cascade of enzymatic reactions to produce effector molecules to clear infectious microbes, immune complexes, post apoptotic cellular debris and thus participate in prevention of autoimmunity. Absolute deficiency of individual complement components and selective deficiency of classical pathway complement components are reported to be associated with severe infections and a high risk for lupus like syndromes. Genetic defect in the expression of which of the following genes would affect complement activation in the classical pathway only?
a. gene encoding DAF
b. gene encoding C2 component
c. gene encoding Factor B
d. gene encoding C9 component
e. gene encoding C1 component
e. gene encoding C1 component
The complement system is increasingly recognized as important in the pathogenesis of tissue injury in vivo following immune, ischemic, or infectious insults. Within the complement system, three pathways are capable of initiating the processes that result in C3 activation: classical, alternative, and lectin. Which of the following complement components is not essential for activation of the alternative pathway?
a. C3 component
b. C2 component
c. C7 component
d. C5 component
e. C6 component
b. C2 component
Phagocytosis is a central event in the innate immune responses that are triggered by the association between ligands on the surface of pathogens and 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 byproducts of complement activation is critical for complement-mediated phagocytosis?
a. C4b
b. C2a
c. C2b
d. C3a
e. C3b
e. C3b
A patient arrives to the emergency department with complaints of difficulty breathing, urticaria, and nausea that all came on suddenly after eating a peanut. The physician suspects that the patient is suffering from an anaphylactic allergic reaction. Which of the
following antibodies will activate which of the following cells responsible for allergic reactions?
a. IgA; mast cells and eosinophils
b. IgG; B cells and T cells
c. IgE; B cells and basophils
d. IgE: mast cells and eosinophils
e. IgA: plasma cells and NK cells
d. IgE: mast cells and eosinophils
A 34-year old male patient presents to the emergency department after stepping on a rusty nail a day prior to hospital visit. He complains of redness, pain, and swelling around the wound. Which cytokine would likely have the greatest effect enhancing macrophage activities in an inflammatory response seen in this patient?
a. IFN-y
b. IFN-a/B
c. IL-1
d. TNF-a
e. IL-6
a. IFN-y
Complete DiGeorge syndrome is a fatal congenital disorder characterized by athymia (the absence of the thymus gland), hypoparathyroidism, and heart defects. Patients with complete DiGeorge syndrome usually die within the first 2 years of life due to severe recurrent infections which are a major problem. A baby born with complete DiGeorge syndrome will have immunological deficiency in which of the following?
a. Monocytes
b. Mast cells
c. B cells
d. T cells
e. Neutrophils
d. T cells
The endothelium is now recognized as not simply being an inert lining to blood vessels, as thought in the 1960s, but a highly specialized, metabolically active interface between blood and the underlying tissues - maintaining vascular tone, thromboresistance, and a selective permeability to immune cells in the circulation. Under the stimulation by agents such as IL-1, the endothelium undergoes changes which allow it to participate in the inflammatory response; this is known as endothelial cell activation. Constitutively activated endothelial cells expressing adhesion molecules will result in which of the following?
a. Continuous transmigration of leukocytes and lymphocytes into tissue, resulting in inflammation
b. Homing of lymphocytes to the secondary lymphoid organs
c. Spatial separation of the T cell zone and B cell follicles in the lymph nodes
d. Movement of activated T cells from the lymph nodes to circulation
e. Chemotaxis of activated T cells to an infection site
a. Continuous transmigration of leukocytes and lymphocytes into tissue, resulting in inflammation
A diagnosis of many chronic inflammatory diseases should be confirmed by histological and immuno-phenotypic examination of a biopsy of lesional tissue. Biopsy is often taken from the most accessible organ, a.k.a. skin if involved; whereas in case of lymphoid tissue involvement, the peripheral lymph nodes should be chosen for biopsy. The main diagnostic feature used is the morphologic and immunological identification of the lesio- nal cells. Upon examination of a biopsy specimen, pathologist found various immune cells accumulated in an inflammatory tissue, but no neutrophils. What is the most likely cause for this result?
a. deficiency in expression of VCAM-1
b. deficiency in expression of IL-8
c. deficiency in expression of ICAM-1
d. deficiency in expression of IFN-y
e. deficiency in E-selectin
b. deficiency in expression of IL-8
TLRs, mammalian homologs of the Drosophila receptor Toll, detect evolutionarily conserved structures expressed by different groups of microbes and play a major role in the elimination of infections by co-activation of the immune system. The family of TLRs consists of 10 members in humans (TLR1–TLR10). TLR8 is one of the least-studied members of the TLR family. To investigate the role of TLR8 in immunological processes, scientists are generated TLR8-deficient (Tlr8–/–) mice by gene targeting. Upon investigation of those mice, it was discovered that TLR 8-deficiency results in which of the following outcome?
a. Reduced or lost signaling caused by recognition of dsRNA
b. Reduced or lost signaling caused by recognition of CpG DNA
c. Reduced or lost signaling caused by recognition of LPS
d. Reduced or loss signaling caused by recognition of PG
e. Reduced or lost signaling caused by recognition of ssRNA
e. Reduced or lost signaling caused by recognition of ssRNA
A virus must use cell processes to replicate. The viral replication cycle can produce dramatic biochemical and structural changes in the host cell, which may cause cell damage and stress. Usually, it is characteristic of many viruses to inhibit MHC I expression in the host cell. If a viral infection, however, allows normal expression of class I MHC by the host cell, defenses of which immune cells will be impacted the most?
A. dendritic cells B. NK cells must use cell processes to replicate. C. neutrophils D. monocytes E. B cells
B. NK cells must use cell processes to replicate.
Ouch! You step on a piece of glass in your backyard. This results in a medium-sized laceration. A couple of hours later, in the ED, you begin to think about innate immune responses. Which of the following is NOT occurring as part of a normal, innate immune response?
a. IL-1 and TNF- α are both produced by tissue macrophages and mast cells after infection.
b. LFA-1 binds to its cognate ligand (ICAM-1) only after the immune cells are activated by an appropriate chemokine.
c. The ligands for E-selectin (sialyl Lewis X Ags) are subsequently expressed in response inflammatory cytokines.
d. L-selectins play a crucial role in the homing of naive B and T cells into the lymph nodes through interacting with high endothelial venules.
e. Chemokine binding to chemokine receptors leads to integrin activation.
c. The ligands for E-selectin (sialyl Lewis X Ags) are subsequently expressed in response inflammatory cytokines.
Innate immune signaling receptors monitor the extracellular space as well as many subcellular compartments for signs of infection, damage or other cellular stressors. The inflammasomes are a group of multimeric protein complexes that consist of an inflammasome sensor molecule, the adaptor protein and caspase 1. Inflammasome formation is triggered by a range of substances that emerge during infections, tissue damage or metabolic imbalances and their activation leads to the release of many inflammatory mediators including some cytokines. Production of which of the following cytokines is mediated by inflammasomes?
a. IL-10 and IL-1B
b. IL-1B and IL-18
c. IL-18 and TNF-a
d. TNA-a and IL-1B
e. IL-10 and TNF-a
b. IL-1B and IL-18
