Quizzes Flashcards
(38 cards)
What is an antigen?
Any molecules that can bind to various types of receptor
Any molecules that can induce a specific innate immune response
Any molecules that can protect against microbes
Any molecules that can induce a specific adaptive immune response
Any molecules that can induce a specific adaptive immune response
Quiz feedback: Molecules such as proteins, nucleic acids, polysaccharides, metals can induce cells of the adaptive immune response (T or B cells) to be activated.
What immunological phenomenon is mediated by the adaptive immunity?
Inflammation caused by neutrophils
Phagocytosis of microbes by macrophages
Killing of infected cells by T cells
Presentation of antigen by dendritic cells to T cells
Killing of infected cells by T cells
Quiz feedback: The adaptive immunity involves cytotoxic T cells that can kill infected cells. It also involves Thelper cells that can activate macrophages that have ingested microbes.
What are the characteristics of naive and memory cells?
Naive and memory cells can survive for long periods of time
Naive cells survive for weeks while memory cells survive for years
Naive cell numbers increase as we age while memory cell numbers decrease
Naive cells respond faster than memory cells to an infectious agent, i.e., are activated and proliferate.
Naive cells survive for weeks while memory cells survive for years
Quiz feedback: Naive cells are short lived and will die if they do not encounter an antigen. Memory cells survive for years without encountering an antigen and can respond immediately when re-encountering an antigen.
What is the function of the lymphatic system?
Allows T cell circulation between different lymphnodes
Allows B cell circulation to the spleen
Allows antigens to accumulate in lymph node
Allows B cells to go to the B cell zone and T cells to go to the T cell zone of the lymph node
Allows antigens to accumulate in lymph node
Quiz feedback: The lymphatic system is the sewer of the body and allows lymph to drain in the lymph nodes where antigens can accumulate and dendritic cells can pick them up.
Your patient is immunodeficient (lack of immune cells) and has been recovering from implant surgery at home and get an infection. He lives 2 hrs from an hospital and drives there to get an iv antibiotic treatment. Which lack of immune cells would have the best outcome for this patient?
neutrophils and monocytes
T and B cells
neutrophils
neutrophils, monocytes, T and B cells
T and B cells
Quiz feedback: Since neutrophils and monocytes are required to control the infection early on, the best outcome for this patient would be to only have a defect in B and T cells.
A gum infection is occurring. What is the first step by which cells of the innate immunity in the tissue identify that microbes have invaded the gum?
They are activated by receptors that recognize soluble molecules produced by microbes.
They express receptors with great diversity for antigens expressed by microbes.
They produce cytokines that allow them to recognize molecules expressed by microbes.
They express receptors with limited diversity allowing them to recognize molecules expressed by microbes.
They produce molecules that activate the complement activation.
They express receptors with limited diversity allowing them to recognize molecules expressed by microbes.
Quiz feedback: Cells of the innate immunity express receptors with limited diversity that are therefore not very specific but allow cells in the tissue to identify microbes.
What is the most important function of the innate immunity at early time-points (days) following a bacterial infection?
Inducing T cells to produce IFNgamma and subsequent macrophage activation.
Controlling the levels of infection until the adaptive immunity is activated.
Activating NLRP3 inflammasome and subsequent IL-1 secretion for recruitment of NK cells.
Inducing plasmacytoid DC production of IFNalpha.
Inducing wound healing M2 macrophages.
Controlling the levels of infection until the adaptive immunity is activated.
Quiz feedback: Controlling the levels of bacterial infection until the adaptive immunity is activated is the main function of the innate immunity at the early time-points.
What is the main function of NK cells?
Phagocytosing microbes
Killing infected cells
Producing IFNalpha for defense against virus
Contributing to inflammation by producing histamine
Activating T cells
Killing infected cells
Quiz feedback: NK cells are the killers of the innate immunity and similarly to cytotoxic T cells they target cells not microbes. They kill cells that are infected with microbes or tumor cells via production of perforin and granzyme.
Match each prompt with the appropriate answer:
Innate immunity and adaptive immunity
with: immediate, non-specific, no memory OR
delayed, specific, memory
Innate immunity: immediate, non-specific, no memory
Adaptive immunity: delayed, specific, memory
The characteristics associated with the innate immunity are immediate response, lack of specificity, and no memory as phagocytes can ingest microbes immediately to kill them. The characteristics associated with the adaptive immunity are delayed response, specificity, memory as it takes 14 days to activate sufficient numbers of T/B cells.
What role do liver-produced acute phase reactant proteins play during an infection?
They induce cytokine production by innate cells which recruit more leukocytes at the infection sites.
They mediate phagocytosis by opsonizing the microbe.
They induce fever which lower DNA and RNA replication necessary for microbe to divide.
They directly mediate microbe killing.
They increase vascular permeability and allow inflammatory cells to enter the tissue.
They mediate phagocytosis by opsonizing the microbe.
Quiz feedback: Liver-produced acute phase reactants are opsonins and mediate microbe phagocytosis via its opsonization (tagging it for ingestion).
How do innate cells mediate inflammation, i.e., identified by swelling, redness, heat & pain, upon infection?
They mediate direct killing of microbes.
They produce molecules that impact other cells at the site.
They produce molecules that bind on the surface of microbes for their ingestion.
They produce molecules that mediate repair.
They produce molecules that “neutralize” the microbe.
They produce molecules that impact other cells at the site.
Quiz feedback: Innate cells produce soluble molecules such as cytokines and histamine upon an infection that increase vascular permeability and attract and activate other cells, leading to inflammation.
What are the systemic effects of inflammatory cytokines released upon an infection?
They only act on the hypothalamus to induce fever.
They only mobilize neutrophils from the bone marrow.
They only induce production of acute phase reactants from the liver.
They only upregulate adhesion molecules on endothelial cells.
They induce fever, mobilize neutrophils from the bone marrow and induce production of acute phase reactants.
They induce fever, mobilize neutrophils from the bone marrow and induce production of acute phase reactants.
Quiz feedback: Cytokines have several systemic effects including induction of fever (hypothalamus, fat and muscle), production of acute phase reactants by the liver and mobilization of neutrophils from the bone marrow.
What are the sequential steps that lead to recruitment of neutrophils at the site of an infection?
Upregulation of adhesion molecules-stable adhesion-activation of integrin-migration through endothelium
Upregulation of adhesion molecules-activation of integrin-stable adhesion-migration through endothelium
Stable adhesion-chemokine release-activation of integrin-migration through endothelium
Activation of integrin-upregulation of adhesion molecules-stable adhesion-migration through endothelium
Upregulation of adhesion molecules-stable adhesion- migration through endothelium-
activation of integrin
Upregulation of adhesion molecules-activation of integrin-stable adhesion-migration through endothelium
Quiz feedback: For recruitment of neutrophils to occur, endothelial cells must upregulate adhesion molecules that allow neutrophils to attach weakly. Integrins on the surface of neutrophils are then activated by chemokines and stable adhesion occurs that leads to migration of the leukocytes through the interendothelial space.
Match each term with their appropriate characteristics.
MHC molecules, MHC Class II, MHC class I with the following:
proteins
alpha and beta chains/CD4
alpha chain/beta2-microglobulin/CD8
MHC molecules - proteins
MHC Class II - alpha and beta chains/CD4
MHC Class I - alpha chain/beta2-microglobulin/CD8
Quiz feedback: MHC molecules only bind protein antigens, i.e., peptides.
MHC I molecules are composed of an alpha chain and beta-microglobulin and bind to CD8.
MHC II molecules are composed of an alpha chain and a beta chain and bind to CD4.
How are extracellular proteins processed for presentation to T cells?
Processed in the endosome/lysosome and loaded onto MHC Class II for presentation to CD4 T cells.
Processed in the reticulum endoplasmic and loaded onto MHC Class II for presentation to CD8 T cells.
Processed in the reticulum endoplasmic and loaded onto MHC Class I for presentation to CD4 T cells.
Processed in the endosome and loaded onto MHC Class II for presentation to CD8 T cells.
Processed in the endosome/lysosome and loaded onto MHC Class II for presentation to CD4 T cells.
Quiz feedback: Extracellular proteins are processed in the endosome/lysosome and loaded onto MHC Class II for presentation to CD4 T cells.
What statement concerning antigen processing and presentation is correct?
Class II molecules are composed of one beta2-microglobulin and one alpha chain.
CD8 T cells recognize peptides associated with MHC class II.
MHC locus consists of two sets of non-polymorphic genes.
Peptides bind outside of the cleft of MHC class I & II molecules.
CD8 T cells recognize peptides associated with MHC class I.
CD8 T cells recognize peptides associated with MHC class I.
Quiz feedback: CD8 T cells recognize only peptides presented on MHC class I molecules.
What statement below reflects accurately antigen presentation to T cells?
Neutrophils present antigen bound to TLR to T cells.
B cells present antigen bound to BCR to T cells.
Macrophages present antigen bound to scavenging receptor to T cells.
DC present antigen bound to MHC molecules to T cells.
DC present antigen bound to microglobulin to T cells.
DC present antigen bound to MHC molecules to T cells.
Quiz feedback: Antigen must be bound to MHC molecules on DC to be presented to TCR on the surface of T cells.
What signals are provided by T helper cells to help macrophages and B cells?
CD40L and IL-2
CD28 and IL-2
CD40 and cytokines
CTLA4 and cytokines
CD40L and cytokines
CD40L and cytokines
Quiz feedback: Thelper cells provide help to B cells and macrophages so they can mediate their function, i.e., make antibodies and kill ingested microbes. One signal is provided by the ligation of CD40 on B cells and macrophages to CD40L on T cells. Cytokines produced by T cells such as IFN gamma is also required to activate macrophages, and induce isotype switching from IgM to IgG for B cells.
What is the difference between naive and effector T cells in a situation in which there is an infection?
Only naive T cells circulate in the body.
Effector T cells live for years while naive T cells have a short life.
Naive T cells contract when they do not encounter antigen.
Effector T cells contract following clearance of pathogens.
Effector T cells and naive T cells have a short life.
Effector T cells contract following clearance of pathogens.
Quiz feedback: Naive T cells have never encountered an antigen. Once they are activated they become effector T cells that proliferate and mediate their function, e.g., fight an infection. Once the pathogen is cleared, most of the effector T cells are being eliminated, i.e., contraction.
What is necessary for thymocytes to survive and completely mature in the thymus?
Expression of CD4 and CD8
Expression of IL-7R
Expression of TCR
Expression of pre-TCR
Expression of preTCR and TCR
Expression of preTCR and TCR
Quiz feedback: Expression of preTCR and TCR determines the ability of T cells to survive in the thymus and mature.
What is the function of Th17 cells in response to infection?
Th17 cells kill cells infected with intracellular microbes.
Th17 cells trigger antimicrobial peptides for clearance of intracellular bacteria.
Th17 cells help recruit neutrophils to the mucosa for clearance of extracellular microbes.
Th17 cells lead to mast cell degranulation for clearance of fungus.
Th17 cells make IL-5 and trigger worm killing by eosinophils.
Th17 cells help recruit neutrophils to the mucosa for clearance of extracellular microbes.
Quiz feedback: IL-17 produced by Th17 cells induce chemokines from other cells/tissues that in turn mediate trecruitment of neutrophils at the mucosa that ingest extracellular microbes and kill them.
How do activated cytotoxic T cells (CTL) kill cells infected with an intracellular microbe?
CTL are activated with help from macrophage to generate MAC which lyse infected cells.
CTL are activated by DC and receive help from Thelper cells to produce perforin and granzyme which lyse infected cells.
CTL are activated by DC and Th1 cells to produce ROS which induce apoptosis of the infected cells.
CTL are only activated by B cells to produce perforin and granzyme that lyse infected cells.
CTL produce nitric oxide that kill infected cells.
CTL are activated by DC and receive help from Thelper cells to produce perforin and granzyme which lyse infected cells.
Quiz feedback: CTL will be reactivated by recognizing their target cells via the interaction of their TCR with the antigen-MHCI complex, and will produce perforin and granzyme. Thelper cells will produce cytokines that help with their activation and differentiation.
Match the T cells with the cytokines they produce.
Th17, Th2, and Th1 with
IL-4, INFy, IL-17
Th17 = IL-17
Th2 = IL-4
Th1 = IFNy
Quiz feedback: Th1 produce IFNγ, Th2 produce IL-4 and IL-5, Th17 produce IL-17 and IL-22.
Cytokines produced by DC and other innate cells determine the fate of naive T cells and the cytokine they will produce. What cytokines accurately induce Th cell differentiation?
IFNgamma induces Th2
IL-12 induces Th17
IL-6 induces Th1
IL-5 induce Th17
IL-4 induces Th2
IL-4 induces Th2
Quiz feedback: IL-4 produced by mast cells and eosinophils during a helminth infection induces the differentiation of Th2 cells.
