Immunology practice 2011 Flashcards
- First signal of B cell activation
Binding to antigen. The second signal is CD40 on the B cell binding to CD40L on the T cell
- Glycolipids from mycobacterium tuberculosis are presented on 2 δγ T cells on
CD1
- Cells of the innate immune system which produce IFN-γ
NK cells
- Surface and membrane immunoglobulins are produced by process involving
alternative splicing.
- These 2 molecules share similar structure and involved in cytotoxic activity
perforin and C9
- Which binds antigen through α1 and α2 domains?
HLA-B (MHCI) All nucleated human cells express HLA-B
- Which HLA molecule inhibits the switch of CLIP in the exogenous processing of antigen?
HLA-DO
- Toll like receptors are involved in
binding of bacterial antigen by macrophage
- All the cytokines below are generated by macrophages or dendritic cells EXCEPT
gamma interferon. Macrophages do NOT produce gamma interferon
- In early stages of a viral infection, 1-2 days after, most of the perforin and granzyme activity is generated by
NK cells
- What cells undergo somatic hypermutation in the germinal centers?
Centroblasts Centroblasts are large, rapidly dividing cells found in germinal centers, and are the cells in which somatic hypermutation is believed to occur. Antibody secreting and memory B cells derive from these cells.
- A 30-year old male who has a history of 4 separate episodes of Neisseria gonorrhea infections which respond to appropriate therapy and can still generate normal chemotactic activity and no other serious medical problems. If he has an isolated component deficiency, which one is more likely?
MAC deficiency MAC= membrane attack complex. It is composed of C5b, C6, C7, C8, and C9, which pokes holes in the bacterial membrane. People with MAC deficiency are prone to Nesseria infections such as Neisseria gonorrhea and Nesseria meningitidis
- Counterpart of CD3 on B cells
Igα.
- The most potent antigen presenting cells to naïve T cells
interdigitating dendritic cells.
- All of these cells share a common lymphoid progenitor EXCEPT
macrophages. They are myeloid cells.
- Consider ALL genetic rearrangement, no calculation required
More than 15 million.
- Which of the following statements is correct to class switch from IgM to IgE?
Variable regions are maintained and constant regions change from μ to ε.
- Affinity maturation is due to
mutations in DNA encoding the V region of an antibody molecule.
- Primary and secondary responses differ in all of the following EXCEPT
first antibody secreted (always IgM).
- Component involved in antigen processing via endogenous pathway is
calnexin
- Which cytokine receptor has a gamma regulatory chain
IL-2
- In the endogenous pathway, peptide will bind to HLA in the presence of
calreticulin and tapasin.
- A recreational soccer play gets hit in the glasses with a soccer ball. His nose is cut by the broken frames and the field is very dirty. He has had all his immunization and had a tetanus booster when he started college last year. What are you going to do?
His long term memory immune response will take care of it.
- If a T cell receptor on a double positive thymocyte binds to a self peptide-self MHC Class II complex, there will be
positive selection of the CD4 T cell
- A patient has been found to be deficient in the expression of CLIP. What can’t he do?
He cannot produce in the exogenous pathway, so no MHC Class II, so no CD4 T cells and he cannot produce cytokines that will allow him to class switch therefore the patient’s immunoglobulin production will be stuck at IgM.
- Gene that is activated immediately after T cell receptor engagement in signal transduction is
NFAT (Nuclear Factor of Activated T cells)
- A 28-year old is given a tetanus booster injection following an injury. Which of the following is not a characteristic of the boy’s immune response to the vaccine?
Not the same as if he were given the shot as the first in a series – this is not a primary response.
- What receptor on NK cells binds MHC Class I and present to target cell
KIR (Killer-cell Immunoglobulin-like Receptor)
- This molecule is important for recruiting effector T cells to the site of infection
VLA-4 and VCAM-1. Effector (activated) T-cells express VLA-4(integrin alpha 4: beta 1). VLA-4 allows the effector T cells to bind to VCAM 1 (CD 106) on activated endothelium and is important for recruiting effector T cells into sites of infection. VLA 4 is strongly expressed after T cell activation.
- The counterpart of γδ T cells among B cells are
CD5+ B cells
- Complement component not require for alternative pathway
C4
- Interferon gamma converts plasma cells into B cells that produce
opsonizing IgG.
- The selection of cells that have undergone somatic hypermutation occurs
follicular dendritic cells in the germinal center.
- Activated complement 1 day after infection
mannose-binding lectin
- Idiotype of an antibody is determined by the amino acid sequence of
variable regions of heavy and light chains.
- Cytokine produced by Th1 cell that inhibits Th2 cell
gamma interferon
- All cell markers are increased in activated macrophage EXCEPT
gamma interferon
- A negative modulator of NK cells is
HLA-B (MHC Class I)
- A 28-year old male is brought into court for child support. His wife insists that he’s the father. Which genetic marker would be helpful?
Allotype
- A researcher has developed a specific antibody to the complement component C3a assume that each administration of the medication prevents the biological effects of C3a. Administration of the antibody is expected to interfere with which of the following biological functions?
Histamine release. C3a and C5a are potent anaphylotoxins; they induce mast cells to release histamine.
- Which marker(s) is present on B cells and could be used to identify them?
CD19 and CD20
- Which one of the following events occurs first in the differentiation sequence of human B cells in bone marrow?
Heavy chain rearrangement
- A T cell clone that is specific for the HIV envelope glycoprotein is found to recognize a peptide of 10 amino acids in length. Which of the following statements is most likely correct?
The T cell is exposed to APC via peptide in MHC Class I.
- In the presence of the following cytokine immature cells differentiate into Th2 cells. What is the cytokine?
IL-4 (from mast cells)
- Which of the following are true concerning chemokine receptors?
They are 7 transmembrane receptor proteins.
- Which of the following cells are more effective in killing a virally infected cells 3 weeks after immune response to the virus which the individual has not been exposed to before?
CD8 (1-2 days will be NK cells)
CD8 (1-2 days will be NK cells)
they don’t produce neutralizing antibodies. They are produced by Th2 cells.
- Which is not produced by Th1 cells?
IL-10
- What is the fate of centrocytes in which somatic hypermutation has resulted in high affinity for receptor antigen?
They process antigen presented to helper T cells. (Only low affinity receptors die.)
- In contrast to immunoglobulins, αβ T cell receptors recognize epitopes present on antigens that are
protein.T cells only recognize short linear proteins presented on MHCII receptors of APCs. The main APC for T cells is the interdigitating dendritic cell, because it constitutively expresses B7. Activated macrophages can also process and present antigen to T cells; and in secondary response B cells present antigen to the T cells via the B-cell T-cell dance.
- One type of lymphocyte syndrome is caused by a genetic defect in MHC Class II transactivators which results in the inability to synthesis MHC Class II and display it on the cell surface
The consequence of this would be that CD4 T cells cannot function.
- Developing B cells that fail to make productive D to J heavy chain rearrangements
die by apoptosis in the bone marrow.
- Which of the following is the predominant route by which antigen are brought from site of infection to lymph node?
Afferent lymphatics
- The 5 isotypes of immunoglobuilins differ from each other in their
constant regions (heavy chains).
- What does a circulating B cell that has never before encountered antigen express on the cell surface?
IgM and IgD
Monomeric IgM acts as antigen-receptor of B cells.
IgD is expressed on mature B cells, but it’s function is unknown
- A workup on a new child reveals low levels of complement C3 in her blood. Which one of the following presentations did the child most likely present?
Recurrent infections with extracellular bacteria. (You need complement and phagocytosis.)
- Vaccinations generate a humoral response to immunogens. Which of the following represents a critical function in humoral response in protecting vaccinated patients from future infections by viruses?
Neutralization
- Positive selection in thymus occurs on thymocytes expressed functional versions of which critical molecule?
T cell receptor
- Which one the following represents the major role of negative selection in the thymus?
Elimination of self-reactive T clones
- Blood sample of an individual with lupus was studied in T cell specificity. Many T cells were discovered to express receptors for autologous antigens. Failure of which process in the thymus leads to large number of autoreactive T cells in patients above?
Negative selection.
- Which cytokine is essential for T cell proliferation?
IL-2
- T helper cells interacting with antigen presenting dendritic cells require signals generated by the direct interaction with the T cell receptor with MHC peptide. Additionally, costimulation is required to amplify the initial T cell receptor signals provided to T cell CD28 molecule interaction with which of the following dendritic molecules?
CD80/CD86 (B7)
- T cells stimulated by peptide MHC complex is displayed on APC in the absence of costimulating undergo which one of the following processes?
Anergy
- Downregulation of T cell activation is achieved by binding of which molecule on T cell and dendritic cell?
CTLA4 binds B7-2
- The intracellular signal produced by antigen binding to T cell receptor is generated by which set of molecules expressed on the T cell membrane?
CD3
- Which molecule on membrane of cells ligand signals apoptosis?
Fas
- Which one of the following cells is a major source of TNF-α, IL-1 and IL-12?
Macrophages
- Which cells are source of IL-4, IL-5, IL-10 and IL-13?
Th2 cells
- If a person has a genetic defect affecting perforin production, which cells in immune function will be affected?
Cytotoxic T cells and NK cells
- A person develops a viral infection and both B and T cells become activated to fight infection. In which way is antigen recognition by B cells different from T cells?
B cells used membrane immunoglobulins to bind antigen in its natural state.
- A person is experiencing a primary infection with a virus. B cells activated in a primary infection secreted which immunoglobulin first?
IgM
- A person develops a viral infection in their respiratory tract. Which antibody class would best protect respiratory epithelial cells from infection?
IgA
- A person develops a viral infection and it spreads from respiratory tract and causes viremia. Which antibody class would be most effective in fighting virus as it spreads through the body?
IgG
- In order for class switching from IgM to IgG, these cells must receive signals. One generated following binding the T helper cells and secreted by helper T cells. What are those T helper cell derived molecules?
CD40L and IFN-γ
- What structure is uniquely found in IgA in breast milk and not serum IgM?
Secretory piece
- A 47 year old woman develops toxic shock following an infection with a strain of Staphylococcus aureus produced TSS toxin (superantigen). The toxin binds directly to MHC Class II molecules on macrophages and which molecule on T cells?
The T cell receptor vβ chain.
- What responses of T cells play a role in the pathogenesis in shock following the binding of TSST-1 and similar molecules?
Exaggerated cytokine secretion
- Macrophages recognize microorganisms through interaction with microbial substance through what type of receptor on macrophages?
Pattern recognition receptors
- Antigen receptors on T and B cells share which similar features?
The variable portions of both receptors are generated by random recombination of genes
- Thymocytes interacting with self-peptides undergo negative selection. The self-peptides in this reaction are turned on by?
AIRE gene
- Persons with helminthic infections mount an immune response that involve IgE and eosinophils. What cytokines are most responsible for this response to occur?
IL-4 and IL-13
- A person develops an extracellular bacterial infection and IgM was made in response. What is the most protective function of IgM in this infection?
Complement activation
- Neutrophils are attracted to site of infection by extracellular bacteria by which two important chemotactic substances?
Complement C5a and IL-8
- Plasma cells secreting IgA are particularly abundant in which body site?
Lamina propria
- Which immune cell recognizes body cells with reduced expression of MHC Class I molecules?
NK cells
- Activation of complement system directly results in which outcome?
Enhanced phagocytosis
- Which of the following is considered a granulocyte?
A. Neutrophils
B. T-cells
B. B-cells
C. NK cells
Neutrophils
- A 54 year female presents with anorexia and some abdominal pain. Fecal smears reveal Tania eggs caused by a parasite. Which one of the following immune system cells is the main defense against this parasite?
Eosinophils
- APC are required for T cell recognition of specific antigen activation. APC accomplish this by presenting antigen in the following molecule?
Major histocompatibility complex
- A female presents with symptoms of systemic lupus, type I diabetes and arthritis. In a genetic analysis, it was found that the patient has no CD4 or T regulatory cells (T-regs). Which of the following is an explanation for the clinical symptoms?
Cannot downmodulate an immune response.
- Following an initial expansion of B cells in response to microbial peptides, a memory corps of B cells is generated and maintained throughout life. Upon challenge with a microbe, the patient is protected from infection. What do memory B cells express on the surface?
IgG (or IgA, IgE)
- Which one of the following represents the mechanism of immune complexes are normally cleared from circulation?
Solubilized by C3b
- Which of the following is the site where lymphocytes can leave the blood and enter lymph nodes and which protein mediates this access?
HEVs and L-selectin
- The difference between tolerance and immunity depends on the maturation status of antigen presenting cells. What is the T cell outcome of antigen presenting by a mature dendritic cell?
Activation
- Antigens from which of the following microbes would be presented on MHC Class I molecules by macrophages?
Influenza virus
- Activation of macrophages is best achieved by what cytokine?
IFN-γ
- Which cells neutralize ROS and nitrogen species in lysosomal enzymes to kill pathogens?
Macrophages
A 4 year old has atopic dermatitis due to severe allergies. Histamine release from which cell type is responsible for clinical manifestation immediately following exposure to this substance?
Mast cells
