Immunology Flashcards
What makes up the cell wall of gram positive bacteria?
Techoic acid
Thick peptidoglycan
What makes up the cell wall of gram negative bacteria?
LPS in outer membrane
Thin peptidoglycan
Intracellular bacteria are primarily taken care of by what type of immune response?
They are shielded from humoral antibodies, so they are eliminated by the cellular immune response
Tissue damage after infection with intracellular bacteria is caused by the host response, in what form does this damage occur?
Inflammation
What general type of bacterial toxin is a component of the bacterial cell wall?
Endotoxin
What general type of bacterial toxin is actively secreted by the bacteria?
Exotoxin
Immune system cells are derived from pluripotent hematopoeitic stem cells in the bone marrow. These can then differentiate into what two progenitor cell types?
Myeloid
Lymphoid
Neutrophils, basophils/mast cells, eosinophils, erythrocytes, monocytes, and platelets all come from what progenitor cell lineage?
Myeloid
B lymphocytes, T lymphocytes, and Natural Killer cells all come from which cell progenitor lineage?
Lymphoid
What innate immune cell performs the effector function of phagocytosis and digestion of microbes?
Neutrophils
What innate immune cell performs the effector function of allergic reactions AND defense against helminths?
Eosinophils
What 2 innate immune cell types are involved in allergic reactions?
Basophils
Mast cells
What is the circulating macrophage precursor?
Monocytes
What innate immune cells performs phagocytosis and digestion of microbes AND antigen presentation?
Macrophages
Mannose (mannan) LPS Peptidoglycan Bacterial CpG DNA dsRNA
The above are all considered ________, which aid in recognition by innate immunity
PAMPs
What are the ligands for the TLR1:TLR2 heterodimer?
Lipopeptides
GPI
What are the ligands for the TLR2:TLR6 heterodimer?
Lipotechoic acid
Zymosan
What is the ligand for TLR3?
dsRNA
What is the ligand for the TLR4:TLR4 homodimer?
LPS
What is the ligand for TLR5?
Flagellin
What is the ligand for TLR7?
ssRNA
What is the ligand for TLR8?
ssRNA
What is the ligand for TLR9?
Unmethylated CpG-rich DNA
What are the 5 signs/symptoms of inflammation?
Heat Redness Swelling Pain Loss of function
What innate immune cell type is the first to arrive at the site of tissue damage? The activation of these leads to respiratory bursts and release of granules to control bacterial growth
Neutrophils
Which interleukin is primarily responsible for NK proliferation?
IL-15
Which interleukin is primarily responsible for synthesis of acute phase proteins in the liver?
IL-6
Type I interferons like IFN-alpha and IFN-beta are involved in response against what type of pathogen?
Viral
IFN-gamma is most important in defense against what type of pathogen?
Bacterial
Which interleukin is of primary importance for generating fever?
IL-1
Which cytokine is of primary importance for activation of endothelial cells?
TNF
What type of mediator in the immune system consists of several circulating plasma proteins that can be induced rapidly by cytokines after infection?
Acute-phase proteins
Examples: MBL, CRP
The complement system may be activated by 3 different pathways, all of which lead to the production of _____, which intiates activation of the ____ component - leading to formation of the membrane attack complex
C3b; C5
Of the properties of adaptive immunity, _________ refers to the ability to recognize and respond to many different pathogens
Specificity
Of the properties of adaptive immunity, _________ refers to enhanced responses to recurrent or persistent infections
Memory
Of the properties of adaptive immunity, _________ refers to the ability to keep pace with rapidly proliferating pathogens
Clonal expansion
Of the properties of adaptive immunity, _________ refers to responses to distinct microbes that are optimized for effective defense
Specialization
Of the properties of adaptive immunity, _________ refers to prevention of injurious immune response against host cells and tissues
Nonreactivity to self Ags
Th1 cells produce _____ that activates macrophages to destroy microbes
IFN-y
T cells only recognize protein Ags, but B cells can recognize a range of Ags. What type of Ags do B cells recognize?
Proteins, polysaccharides, lipids, and nucleic acids
What are the only APCs capable of presenting to naive T cells?
Dendritic cells
T-cell receptor complexes consist of 2 Ag-binding chains: _______ and _______. TCRs are identical in each individual T cell. Although the TCR has a short cytoplasmic tail, signaling occurs via _______, which is always expressed with the TCR. Each T helper cell expresses _____ which is required for interaction with the APCs. CTLs express the co-receptor molecule _______.
Alpha; beta
CD3
CD4
CD8
What are the 3 professional APCs?
Dendritic cells
Macrophages
B cells
Ag processing for class II MHCs:
____________ Ags are processed in the lysosomes of professional APCs. The alpha and beta chains of MHC II are produced in the _________. A specialized invariant chain ________ prevents binding of endogenous peptides in endosomes. Endosomes fuse with lysosomes. Enzymes within the lysosome degrade CLIP, enabling binding of exogenous peptide Ags into MHC II.
Exogenous
ER
CLIP
Class II MHCs allow presentation to what type of T cells?
CD4+ T helper cells
Ag processing for Class I MHCs:
Microbial ___________ are degraded by proteasomes to peptides. Degraded peptides are carried into the ______ by transporters of antigenic peptides (TAP1 and TAP2). Peptides are loaded into the MHC class I complex. The complex is routed through the _______ to the plasma membrane.
Proteins
RER
Golgi
Class I MHCs present processed peptides to what type of T cell?
CD8+ CTLs
Which of the following are not properties of MHC molecules?
A. Co-dominant expression
B. Polymorphic genes
C. Class II expression on all nucleated cells
D. Class I expression on all nucleated cells
E. All of the above are properties of MHC molecules
C.
Class II are only expressed on professional APCs
For full activation of CD4+ T cells, at least ______ TCRs must bind the Ag simultaneously. Cross-linking of those leads to signaling and activation. _____ and ______ are signaling subunits noncovalently attached to the TCR.
Two
CD3; zeta chains
The first signal in activation of CD4+ T cells is the TCR complex recognizing Ag, but this is not enough to activate the T cell. What is the second signal?
Co-stimulation via B7-CD28
After activation by Ag and costimulation, naive CD4+ T cells may differentiate into specific subsets of Th1 and Th2 cells. The fate is controlled by cytokines. ______ produced by microbe-activated macrophages and DCs stimulates differentation into Th1 CD4+ cells.
IL-12
If there is no IL-12, the T cells produce ______ that stimualtes differentation into Th2 cells
IL-4
Compare Th1 to Th2 in terms of what type of immunity they provide
Th1 = cell-mediated
Th2 = Ab-mediated
What T-cell specific cytokine is responsible for T cell growth stimulation?
IL-2
What T-cell specific cytokine is responsible for B cell switching to IgE?
IL-4
What T-cell specific cytokine is responsible for activation of eosinophils?
IL-5
What T-cell specific cytokine is responsible for activation of macrophages?
IFN-y
What T-cell specific cytokine is responsible for inhibition of T cell activation?
TGF-B
B cells can produce various classes of Abs, but only after Ag-activated B cell is helped by activated CD4+ T helper cells and becomes a _______ cell
Plasma
Where does T and B cell interaction occur?
In a local lymph node
During T cell mediated activation of a B cell:
The B cell presents Ag to helper T cell –> Helper T cell is activated and begins expressing ______, secretes cytokines –> B cells are activated by ______ engagement and cytokines –> B cell proliferation and differentiation
CD40L
CD40
In terms of Ab structure and functional domains, light chains come in two varieties, called ______ and ________. The different heavy chains correspond to their class and are given greek letters; these correspond to what FIVE Ab classes???
Kappa; lambda
IgG IgM IgA IgD IgE
An Ab is a tetramer of 2 pairs of identical heavy and light chains. Both heavy and light chain molecules have variable and constant domains.
Which region confers Ag recognition?
Which region interacts with cell surface receptors?
Which region confers flexibility?
Which region specifies specific biological activity?
Ag recognition = Variable region aka F(ab’)2
Cell surface receptors = Constant region aka Fc
Flexibility = Hinge domain
Biological activity = Fc fragment
Which Ab isotype has 4 subclasses? Which Ab isotype has 2 subclasses?
IgG has 4: IgG1-4
IgA has 2: IgA1-2
Describe each Ab isotype in terms of its number of subunits
IgG = monomer IgM = pentamer IgA = dimer IgD = monomer IgE = monomer
What is the principle effector function of IgM?
Complement activation
What is the principle effector function of IgG?
Fc receptor-dependent phagocyte responses, complement activation, neonatal immunity (placental transfer)
What is the principle effector function of IgE?
Immunity against helminths, mast cell degranulation
What is the principle effector function of IgA?
Mucosal immunity
What cytokine is associated with production of IgG?
IFN-y
What cytokine is associated with production of IgE?
IL-4
What cytokine is associated with production of IgA?
TGF-B
The gamma-globulin fraction of serum is primarily composed of 3 Ab isotypes: _______, ________, and ______.
______ is present at low concentrations.
Only traces of ______ are found in circulation
IgG, IgA, IgM
IgE
IgD
