IS 2 Flashcards
Positive selection in the thymus occurs when thymocytes express functional versions of which critical molecule?
CD28 Fc receptor MHC class I MHC class II T-cell receptor (TCR)
T-cell receptor (TCR)
Which one of the following represents the major role of negative selection in the thymus?
Expansion of nonself-reactive T cells
Maturation of professional antigen presenting cells such…
Elimination of self-reactive T cells
Expression of T-cell receptors on mature T cells
Differentiation of Th1 and Th2 CD4+ T cells
Elimination of self-reactive T cells
A blood sample from an individual with systemic lupus erythematosus was studied in a research project mapping-cell
receptor specificities. Many T cells were discovered to express receptors specific for autologous antigens. Failure of which process in the thymus leads to a large number of autoreactive T cells in the patient’s blood?
Affinity maturation Antigen processing Hematopoiesis Negative selection Receptor editing
Negative selection
T helper cells interacting with antigen-presenting dendritic cells require signals generated by the molecular interactions of the T-cell receptor with the MHC–peptide complex. Additionally, costimulation is required to amplify the initial TCR signals provided through the T cell CD28 molecule interaction with which one of the following dendritic cell molecule(s)?
CD4 CD8 CD45 CD80/86 CD152
CD80/86
Dendritic cells, macrophages, and what other cell types are considered “professional antigen-presenting cells,” capable of antigen presentation to T helper cells?
B cells Basophils Eosinophils Mast cells Neutrophils
B cells
Antigens from which one of the following microbes would be presented on MHC class I molecules by macrophages?
Ascaris lumbricoides Candida albicans Haemophilus infl uenzae Influenza virus Streptococcus pneumoniae
Influenza virus
Which cells utilize reactive oxygen and nitrogen species and lysosomal enzymes to kill pathogens?
Cytotoxic T cells Natural killer T (NKT) cells Natural killer (NK) cells Macrophages Th1 cells
Macrophages
If a person had a genetic defect affecting perforin production, which cells and immune function would be affected?
Cytotoxic T cells and natural killer cells/cell killing
Dendritic cells/antigen presentation
Eosinophils and basophils/granule production
Macrophages and neutrophils/phagocytosis
Mast cells/fusion of granules tocell membrane
Cytotoxic T cells and natural killer cells/cell killing
Which immune system cell is primarily responsible for the formation of granuloma in the lungs of tuberculosis patients?
Cytotoxic T cells Dendritic cells Eosinophils Natural killer cells Th1 cells
Th1 cells
Macrophages recognize microorganisms through the interaction of microbial substances with what type of receptors on macrophages? Antigen receptors Complement receptors Fc receptors Membrane immunoglobulin Pattern recognition receptors
Pattern recognition receptors
Thymocytes interacting with self-peptides undergo negative selection. The self-peptides in this reaction as:
Allergens Tolerogens Haptens Immunogens Antigens
Tolerogens
Neutrophils are attracted to the sites of extracellular bacterial infections by which two important chemotactic substances?
Bacterial mannose and lipopolysaccharide
Histamine and complement C3b
Interleukin-7 and interleukin-16
Complement C5a and interleukin-8 (CXCL-8)
Leukotriene B4 and granulocyte colonystimulating factor (G-CSF)
Complement C5a and interleukin-8 (CXCL-8)
Which immune system cells recognize body cells with reduced expression of MHC class I molecules?
Cytotoxic T cells Dendritic cells Macrophages Natural killer cells Neutrophils
Natural killer cells
Which one of the following leukocytes is considered a “granulocyte”?
Macrophage Neutrophil Dendritic cell Natural killer cell Natural killer T cell
Neutrophil
A 45-year-old female presents with anorexia and some abdominal pain. Fecal smears reveal the presence ofTaenia eggs, products of a parasitic tapeworm infection. Which one of the following cells would be most effective in defense against this parasite?
Platelets Erythrocytes Neutrophils Eosinophils Monocytes
Eosinophils
Antigen-presenting cells (APCs) are required for T-cell recognition of specific antigen and activation. APCs accomplish this task by presenting antigen in the context of which of the following molecules?
T-cell receptor (TCR) Toll-like receptor (TLR) Major histocompatibilitycomplex (MHC) Killer inhibitory receptor (KIR) Fc receptor (FcR)
Major histocompatibilitycomplex (MHC)
The difference between tolerance and immunity depends upon the maturation status of the antigen-presenting dendritic cells. What is the T-cell outcome of an antigen-presentation event by a mature dendritic cell?
Anergy
Apoptosis
Activation
Ignorance
Activation
What is a characteristic of the adaptive immune response and not of the innate response?
Physical barriers Clonal expansion of effector cells Chemical barriers Inflammatory mediators Phagocytosis
Clonal expansion of effector cells
What is the principal function of class I and class II MHC molecules?
They are mediators of T-independent B-cell responses.
They bind peptide antigens for presentation to antigen-specif…
They help in endocytosis of antigens by phagocytic cells.
They bind carbohydrate antigens directly for presentat…
They display peptide antigens for review by antigen-specific…
They display peptide antigens for review by antigen-specific…
MHC class I molecules need to bind peptide antigens to fold properly and to be expressed at the cell surface. What would you expect to be the most common health problem in a child with a defect in the function of the peptide transporter (TAP) found in the endoplasmic reticulum?
Chronic upper respiratory viral infections Parasitic infections Infections with encapsulated bacteria Pronounced allergies to household pets Autoimmune disease
Chronic upper respiratory viral infections
Which major antibody molecule has the ability to cross the placenta?
IgG IgA IgM IgE IgD
IgG
In any given immunoglobulin molecule, the light chains are:
Identical to each other in theirantigenic determinants
Identical to each other except intheir hypervariable regions
Of related but different aminoacid sequences
Identical to each other except intheir overall domain structure
Identical to each other
Identical to each other
NK cells express a killer immunoglobulin-like receptor, which
recognizes?
MHC class I molecules MHC class II molecules Cell adhesion molecules Glycophospholipid molecules CD40 molecules
MHC class I molecules
A cell that plays a critical role in the innate immune response and kills virus-infected cells is:
T cell Neutrophil NK cell Macrophage B cell
NK cell
A cytokine that activates cells to express MHC class II antigens and protects cells from virus replication is:
Interferon-α IL-6 Interferon-γ TNF-α IL-10
Interferon-γ
The interaction of a pathogen molecule with its specific TLR directly results in which of the following?
Presentation of pathogen molecules to helper T cells
Cell activation and production of cytokines and chemokines
IgG production
Immunoglobulin class switching
Phagocytosis
Cell activation and production of cytokines and chemokines
A patient has a complete blood count performed, and a peripheral blood smear is examined. The blood smear contains a cell that is approximately 10 microns in diameter with a dense basophilic nucleus that almost fills the cell. Which of the following is an important function of this cell?
Abscess formation Antibody secretion Destruction of virus-infected cells Phagocytosis Release of vasoactive a mines
Destruction of virus-infected cells
During his annual physical examination, a 50-year-old African-American man complains to his physician of fatigue, swollen cervical lymph nodes, and pain in his spine and ribs. Serum electrophoresis shows a spike of protein in the gamma region. The abnormal immunoglobulin is determined to be of the IgG isotype. An IgG molecule is composed of which of the following?
One alpha, one gamma, and two kappa chains
One gamma chain and two kappa chains
Two gamma chains, one kappa, and one lambda chain
Two gamma chains and two kappa chains
Two mu chains and two kappa chains
Two gamma chains, one kappa, and one lambda chain
A 64-year-old man complains of difficulty breathing and a productive cough. Physical examination yields a fever and blood-tinged sputum containing acid-fast bacilli. X-ray analysis reveals
several opacities in the upper lobe of the left lung. Needle biopsy of one of these masses reveals lymphocytes and activated macrophages. Which of the following cytokines is most strongly associated with the formation of this lesion?
Interferon-a Interferon-y Interleukin -1 Interleukin-2 Tumor necrosis factor-a
Tumor necrosis factor-a
Which of the following are characteristics of acute-phase reactants?
Rapid increase following infection Enhancement of phagocytosis Nonspecific indicators of inflammation All of the above
All of the above
Which of the following plays an important role as an external defense mechanism?
Phagocytosis
Lysozyme
C-reactive protein
Complement
Lysozyme
The process of inflammation is characterized by all of the following
except
increased blood supply to thearea. migration of white blood cells. decreased capillary permeability. appearance of acute-phase reactants.
decreased capillary permeability.
