Exam 3 Practice Set 1 Flashcards
Two subpopulations of TH cells, designated TH1 and TH2, can be distinguished in vitro by the cytokines they secrete. Which cytokines are typically secreted by the TH2 subset? A. IFN‐γ, TNF‐β, IL‐2 B. IL‐4, IL‐5, IL‐10 C. IL‐12, IL‐6, IL‐1 D. IL‐8, RANTES, MIP‐1α 12
B. IL‐4, IL‐5, IL‐10
The IL‐2 receptor occurs in three forms that exhibit different affinities for IL‐2. These include the low affinity monomeric IL‐2Rα, the intermediate affinity dimeric IL‐2Rβγ, and the high‐affinity trimeric IL‐2Rαβγ. Which cells typically express the high‐affinity trimeric IL‐2Rαβγ? A. Resting CD8+ T cells B. Neutrophils and macrophages C. Activated CD4+ and CD8+ T cells D. Naïve B cells
C. Activated CD4+ and CD8+ T cells
The NALP‐3 inflammasome is assembled in the cytosol in response to danger signals (bacterial products) and plays an important role in the regulation of IL‐1β. What is the consequence of activation and assembly of the NALP‐3 inflammasome?
A. pro‐IL‐1β is synthesized
B. pro‐Caspase‐1 is cleaved into active Caspase‐1, which cleaves pro‐IL‐1β into active IL‐1β
C. IL‐1R antagonist (IL‐Ra) is produced which blocks the IL‐1 receptor, inhibiting binding of
IL‐1β to its receptor
D. Pro‐IL‐1 β is rapidly degraded
B. pro‐Caspase‐1 is cleaved into active Caspase‐1, which cleaves pro‐IL‐1β into active IL‐1β
Septic shock may develop when bacterial components are recognized by dendritic cells and macrophages. Which two proinflammatory cytokines are rapidly elevated during early phases of bacterial septic shock? A. TNF‐α and IL‐1β B. IL‐2 and TNF‐β C. IL‐4 and IL‐5 D. TNF‐β, TGF‐β
A. TNF‐α and IL‐1β
Important function of NK‐cells is to kill virus‐infected cells and tumor cells. What is correct of the statements below:
A. NK‐cells use their KIR receptors for killing target cells
B. NK‐cells make memory cells
C. NK‐cell killing is stimulated by HLA molecules
D. NK‐cells are part of the innate immune system
D. NK‐cells are part of the innate immune system
The biological function of HLA II molecules is to present antigens to T helper cells. What is correct of the statements below?
A. Class II molecules are expressed on B‐cells
B. Class II molecules are expressed on resting T‐cells
C. HLA‐DR‐antigens have monomorphic β‐chains
D. Allelic exclusion is a characteristic of HLA molecules
A. Class II molecules are expressed on B‐cells
Immune responses in the adaptive immune system have to be turned on, and off again when the adequate reaction is fulfilled. Which statement below is correct?
A. CTLA‐4 is expressed on activated B‐cells
B. CTLA‐4 gives a negative signals to B‐cells
C. CTLA‐4 on T‐cells competes with CD28 for binding to B7 on B‐cells
D. CTLA‐4 gives an activation signal to T helper cells
C. CTLA‐4 on T‐cells competes with CD28 for binding to B7 on B‐cells
Thymus is a central lymphoid organ for cellular maturation and selection. Which of the following cells are negatively selected in the thymus?
A. Autoreactive B‐cells
B. Autoreactive NK‐cells
C. T‐cells recognizing allogeneic MHC
D. T‐cells with strong affinity to autologous MHC
D. T‐cells with strong affinity to autologous MHC
Members of the immunoglobulin superfamily are mainly molecules with a receptor function. Which of the following molecules have the MHC II as its natural ligand? A. CD2 B. CD3 C. CD4, TCRαβ D. CD28
C. CD4, TCRαβ
Rituximab is a monoclonal anti‐CD20 antibody used in the treatment of CD20+ B‐cell non‐ Hodgkin’s lymphoma. How can this antibody prevent tumor progression?
A. By tagging the tumor cells for destruction by activated cytotoxic T‐cells and/or NKT cells
B. By tagging suppressor T‐cells for elimination by NK cells
C. By tagging the tumor cells for destruction mediated by the complement system and/or by inducing antibody‐dependent cell‐mediated cytotoxicity
D. By targeting toxins to the malignant cells
C. By tagging the tumor cells for destruction mediated by the complement system and/or by inducing antibody‐dependent cell‐mediated cytotoxicity
Autoimmunity is an inappropriate adaptive immune response against self‐proteins. What is a likely mechanism in breakdown of tolerance?
A. Primary targets of autoimmunity are cells that express high levels of tissue antigens
B. Cells that leave their designated tissues and enter other tissues can elicit autoimmunity
C. Cells chronically infected by viruses cannot longer dampen immune responses and therefore promote a break in tolerance to its own antigens
D. Defects in the apoptotic machinery allows self‐reactive adaptive immune cells to proliferate
E. Repeated injury and the following inflammation can cause autoimmunity
E. Repeated injury and the following inflammation can cause autoimmunity
During the intracellular phase viruses are detected by cytosolic immune proteins as well as by cytotoxic T cells recognizing viral peptides presented on MHC class I. Why are live viruses better than killed viruses as vaccines?
A. Killed viruses are degraded in lysosomes and are therefore inefficiently presented by the MHC class I pathway
B. Killed viruses are recognized and destroyed faster since they cannot evade immunity
C. Killed viruses do not activate complement
D. Only replicating viruses contain ligands that activate the Toll‐like receptors in antigen presenting cells
E. Live viruses infect non‐immune cells, whereas killed viruses only enter phagocytes
E. Live viruses infect non‐immune cells, whereas killed viruses only enter phagocytes
Cross‐presentation is a feature found in dendritic cells and in tissue macrophages. What is the sequence of events? A. Antigen/microbe/cell is phagocytized, degraded in lysosomes, loaded onto MHC class II and transported to the surface B. Antigen is translated to protein from phagocytized microbial mRNA in the cytosol, transported into ER, loaded onto MHC class I and transported to the surface C. Antigen/microbe/cell is phagocytized and broken down in lysosomes, antigens are transported to cytosol for proteosomal degradation, transported to ER, loaded onto MHC class I and transported to the surface D. Antigen/microbe/cell is phagocytosed, transported to ER, degraded by proteasomes, loaded onto MHC class I, and transported to the surface E. Antigen/microbe/cell is phagocytosed, degraded in lysosomes, loaded onto MHC class I and transported to the surface
C. Antigen/microbe/cell is phagocytized and broken down in lysosomes, antigens are transported to cytosol for proteosomal degradation, transported to ER, loaded onto MHC class I and transported to the surface
NK cells are innate immune cells with important functions against viral infections. What is the main mechanism of recognition of infected cells?
A. Viral epitopes presented by non‐classical MHC molecules
B. Through by‐stander effects initiated by neighboring activated dendritic cells
C. By cross‐presentation of viral epitopes by follicular dendritic cells in the lymph nodes
D. By specific anti‐viral antibodies on the infected cell surface
E. By binding of viral epitopes to Toll‐like receptors (TLRs) on the NK cell
D. By specific anti‐viral antibodies on the infected cell surface
An essential part of the innate immune system is phagocytosis followed by destruction of the phagocytized particle/microbe followed by antigen presentation. What cells are considered professional phagocytes?
A. Granulocytes, monocytes, macrophages, dendritic cells
B. Macrophages, dendritic cells, B cells
C. Granulocytes, monocytes, macrophages, B cells
D. Antigen presenting cells
E. All innate immune cells
B. Macrophages, dendritic cells, B cells
The internal immune system is mainly enforced by leukocytes; the leukocytes have different half‐lives and are constantly generated, about 1011 each day in a human adult. Where are they generated?
A. All leukocytes originate from the bone marrow
B. All leukocytes except T cells originate from the bone marrow
C. B cells originates from the bone marrow, T cells from the thymus and innate immune cells are formed throughout the body
D. Leukocytes originate from most tissues in the adult body
E. Innate immune cells originate from the bone marrow, lymphocytes from lymphoid tissue
B. All leukocytes except T cells originate from the bone marrow
Immunological memory is important for an effective vaccine. Which one of the following statements describes the underlying mechanisms for this most accurately?
A. Macrophages and B cells have developed optimal effector mechanisms towards the antigen contained in the vaccine and can during an infection with this antigen respond faster and more effectively
B. T ‐and B‐cells have developed effector mechanisms towards the antigen contained in the vaccine and can during an infection with this antigen respond fast and effectively to prevent disease
C. T ‐and B‐cells have developed effector mechanisms towards a certain virus or bacteria and can prevent us from infection
D. NK cells, T ‐and B‐cells have developed effector mechanisms towards the antigen contained in the vaccine and
B. T ‐and B‐cells have developed effector mechanisms towards the antigen contained in the vaccine and can during an infection with this antigen respond fast and effectively to prevent disease
B‐cells can produce five different classes of antibodies. Antibodies belonging to the different classes have different effector mechanisms. Transport of antibodies from mother to the fetus (transcytosis) is important to protect the child against disease during the first months after birth. Which one of the following statements describes this situation most accurately?
A. Transportation of IgM and IgG to the fetus provides the child with antibodies that, through opsonization and neutralization, may protect against several diseases
B. Transportation of IgG and IgE to the fetus leads to protection of the child through different effector mechanisms towards the same antigens that the mother has generated antibodies towards
C. Transportation of IgM to the fetus provides the child with antibodies that, through opsonization and neutralization, may protect against several diseases
D. Transportation of IgG to the fetus leads to protection of the child through different antibody effector mechanisms towards the same antigens that the mother has generated antibodies towards
D. Transportation of IgG to the fetus leads to protection of the child through different antibody effector mechanisms towards the same antigens that the mother has generated antibodies towards
The germinal center reaction is an important part of the antigen‐dependent development of B cells. Through which mechanisms does antigen‐dependent development of B cells occur?
a. Clonal expansion, somatic hypermutation and class switching
b. Clonal expansion, antibody production and activation of the B cell
c. Somatic hypermutation, immunoglobulin rearrangement and activation of the B cell
d. Clonal expansion, proliferation, class switching and allelic exclusion
a. Clonal expansion, somatic hypermutation and class switching
Naïve B cells require several signals in order to become activated. Which are these signals?
a. Signal 1 from antigen through the B cell receptor and signal 2 from activated CD4 T‐cells
b. Signal 1 from antigen through the B cell receptor and signal 2 from CD8 positive T‐cells
c. Signal 1 from CD4 positive T‐cells and signal 2 from follicular dendritic cells
d. Signal 1 from CD4 positive T‐cells and signal 2 from cytokines produced by macrophages
e. Signal 1 from antigen through MHC molecules and signal 2 from cytokines produced by macrophages
a. Signal 1 from antigen through the B cell receptor and signal 2 from activated CD4 T‐cells
