Term
| What is the sole function of B cell immunity? |
|
Definition
|
|
Term
| What are the functions of immunoglobulins? |
|
Definition
| They remove pathogens by binding themselves, neutralization, or opsonization |
|
|
Term
| What is the mechanism by which antibodies binding to sites on pathogens prevent growth of the pathogen and/or its entry into cells? |
|
Definition
|
|
Term
| What is the coating of the surface of a pathogen or other particle with any molecule that makes it more readily ingested by phagocytes? |
|
Definition
|
|
Term
| How does opsonization remove pathogens? |
|
Definition
| By inducing phagocytosis and complemented cell lysis |
|
|
Term
| Why does B cell activation take 7-10 days? |
|
Definition
| Need CD4+ T cell for activation, isotype switching, and affinity maturation |
|
|
Term
| What antibody is generally produced to activate B cells without T cell help? (T-independent antigen) |
|
Definition
|
|
Term
| What 3 signals does B cell activation require? |
|
Definition
1. Cross-linking of surface Igs
2. B cell co-reptor
3. CD40-CD40 ligand binding |
|
|
Term
| What is the B cell co-receptor composed of? |
|
Definition
|
|
Term
|
Definition
| Binds to complement protein C3d |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| For most primary immune responses, activation of pathogen-specific B cells requires what? |
|
Definition
|
|
Term
| What are antigens that can stimulate B cells to produce antibodies without T cell help? |
|
Definition
| Thymus-independent antigens (TI antigens) |
|
|
Term
| T/F: During a TI antigen response, very little isotype switching occurs and the isotype is predominately IgG. |
|
Definition
| False, IgM is predominately produced |
|
|
Term
| T/F: During a TI antigen response, very little somatic hypermutation and affinity maturation occur. |
|
Definition
|
|
Term
| What are usually surface bacterial surface molecules with highly repetitive epitopes? |
|
Definition
|
|
Term
| What are antigens that activate antibody secretion from B cells by activating additional receptors called? |
|
Definition
|
|
Term
| What are 2 examples of a TI-1 antigen? |
|
Definition
| Lipopolysaccharide (LPS) and bacterial DNA |
|
|
Term
| What recognizes the TI-1 antigen lipopolysaccharide? |
|
Definition
| TLR4 & CD14 as well as the B cell receptor and co-receptor |
|
|
Term
| T/F: T1-antigens can also activate B cells specific to other "non-TI" antigens. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What are antigens that do not activate additional signal pathways? |
|
Definition
|
|
Term
| What is an example of a TI-2 antigen? |
|
Definition
| Cross-linking of B cell receptors |
|
|
Term
| What is the function immature dendritic cells? |
|
Definition
| To bring the pathogen and their antigens from sites of infection to the secondary lymphoid tissues |
|
|
Term
| What spreads an infection? |
|
Definition
|
|
Term
| What activates dendritic cells and differentiates them into effector CD4+ T cells? |
|
Definition
|
|
Term
| What attracts B cells into T cell zones of the lymph node? |
|
Definition
|
|
Term
| T/F: Mechanisms in which B cells migrate into the lymph node are different from those used by T cells. |
|
Definition
|
|
Term
| What happens to B cells that are specific for an antigen? |
|
Definition
| They become trapped in the T cell zone where they process and present peptides on MHC class II molecules |
|
|
Term
| What are T cells that recognize the same antigen, although the epitope could be different? |
|
Definition
|
|
Term
| What causes an immunological synapse? |
|
Definition
| T cell:B cell interactions |
|
|
Term
| What happens during an immunological synapse? |
|
Definition
1. The T cell is induced to express CD40 ligand.
2. B cells are induced to upregulate cell adhesion molecules.
3. The T cells cytoskeleton is rearranged.
4. Cytokines are secreted (IL-4 most important) |
|
|
Term
| What is the most important cytokine secreted by the T cell? Why? |
|
Definition
| IL-4 because it induces B cell proliferation and differentiation |
|
|
Term
| During B cell maturation CCR7 binds to what? |
|
Definition
|
|
Term
| T/F: CCL19 is recognized by all B cells. |
|
Definition
|
|
Term
| Where is the primary focus for expansion of antigen-activated B cells? |
|
Definition
|
|
Term
| Where is the secondary focus for expansion of antigen-activated B cells? |
|
Definition
|
|
Term
| Where T cell:B cell conjugate pairs migrate? |
|
Definition
| Primary follicle or medullary cords |
|
|
Term
| What do plasma cells secrete? |
|
Definition
|
|
Term
| How does IgM reach the site of infection? |
|
Definition
|
|
Term
| What influences B cells to stay in the medullary cords and further differentiate into plasma cells? |
|
Definition
|
|
Term
| Where does isotype switching first occur in B cell activation? |
|
Definition
| From B cells in the medullary cords |
|
|
Term
| What % of proteins is made by IgM? |
|
Definition
|
|
Term
| What are Follicular Dendritic cells (FDCs) essential for? |
|
Definition
| Producing B cells that have undergone affinity maturation and isotype switching |
|
|
Term
| How long can FDCs hold antigens? |
|
Definition
|
|
Term
| What is an example of a long-lasting depository of antigen by FDC? |
|
Definition
|
|
Term
| How is HIV retained at the cell surface? |
|
Definition
| Complement binds HIV and FDCs have CR1 and CR2 that will bind to the virus and retain the pathogen at the cell surface |
|
|
Term
| What is a pathogen or antigen coated with complement called? |
|
Definition
|
|
Term
| T/F: Immune complex are internalized. |
|
Definition
| False, they are retained at the surface |
|
|
Term
| What are bundles of immune complexes on a give dendrite of a FDC called? |
|
Definition
| Iccosomes (iummune-complex coated bodies) |
|
|
Term
| T/F: Cognate helper T cell are still attached to B lymphoblasts when they migrate into the primary follicle of the B cell. |
|
Definition
|
|
Term
| What helps B cells undergo isotype switching and somatic mutation? |
|
Definition
| FDCs and CD4+ T cells (production of acitvation-induced cytidine deaminase) |
|
|
Term
| What cytokines secreted by FDCs cause B cells to divide rapidly and become large metabolically active centroblasts? |
|
Definition
|
|
Term
| What are the main purposes of centroblasts? |
|
Definition
1. Generate a large population of B cells with switched isotypes
2. Generate a large population of B cells with many different combinations of mutations in the V-region genes
3. Affinity maturation |
|
|
Term
| T/F: Centroblasts do not express immunoglobulin |
|
Definition
|
|
Term
| What causes CD4+ T cells to produce the enzyme activation-induced cytidine deaminase? |
|
Definition
| Expression of CD40-ligand |
|
|
Term
| What causes the primary follicle to become the secondary follicle? |
|
Definition
|
|
Term
| What contains rapidly dividing B and T cells? |
|
Definition
|
|
Term
| Where does somatic hypermuation occur? |
|
Definition
|
|
Term
| Composed of tightly packed centroblasts? |
|
Definition
|
|
Term
| Smaller more mature forms of B cells that dive more slowly and express immunogloblulin? |
|
Definition
|
|
Term
| As centrocytes mature where do they migrate? |
|
Definition
| From the dark zone to the light zone |
|
|
Term
| What is the light zone composed of? |
|
Definition
| Centrocytes, FDCs, and CD4+ T cells |
|
|
Term
| Centrocytes die by apoptosis within a short period of time unless: |
|
Definition
1. Their surface immunoglobulin is bound by antigen
2. CD40 is bound by CD40 ligand |
|
|
Term
| What must centrocytes do to survive? |
|
Definition
| Must compete with each other for access to FDCs and then for CD4+ T cells |
|
|
Term
| What takes place when a centroblast becomes a centrocyte? |
|
Definition
|
|
Term
| What type affinity does somatic hypermutation produce? |
|
Definition
|
|
Term
| What is the source of antigen for centrocytes? |
|
Definition
|
|
Term
| What happens if a centrocyte binds to an antigen displayed on a FDC? |
|
Definition
1. A synapse is formed
2. FDC delivers survival signals to the B cell
3. The B cells will then migrate to the outer regions of the light zone where it presents antigen to CD4+ T cells via MHC class II molecules
4. Recognition of the peptide:MHC class II complex by the T cell receptor and CD40:CD40 ligand which prevents apoptosis |
|
|
Term
| What happens to apoptotic centrocytes? |
|
Definition
| Phagocytized by macrophages |
|
|
Term
| The process where only centrocytes with the highest affinity for antigen are selected to survive and become plasma cells or long-lived memory cells? |
|
Definition
|
|
Term
| Th1 cytokines (IFN-γ)induce immunoglobulin swithcing to: |
|
Definition
|
|
Term
| Th2 cytokines (IL-4, IL-5, and TGF-β) induce isotype switching to? |
|
Definition
| IgG1, IgG2b, IgA, and IgE |
|
|
Term
| Induction of isotype switching requires what? |
|
Definition
| Cytokines and the binding of CD40 ligand and CD40 |
|
|
Term
| What differentiates a B cell from a plasma cell? |
|
Definition
| Surface Ig, MHC expression, Ig secretion, growth, somatic hypermutation, isotype switching |
|
|
Term
|
Definition
| Induces antigen specific centrocytes to differentiate into plasma cells |
|
|
Term
|
Definition
| Induces antigen specific centrocytes to differentiate memory B cells |
|
|
Term
| T/F: Isotype switching diversifies the Fc region of the immunoglobulin. |
|
Definition
|
|
Term
| What are the 2 functions of the Fc region |
|
Definition
1. To deliver antibodies to sites that would otherwise be inaccessible
2. To enhance the delivery of antigen or pathogen to the proteins or cells that would then destroy or neutralize the pathogen |
|
|
Term
| What is the first antibody secreted during an infection? |
|
Definition
|
|
Term
| What is the role of pentameric IgM? |
|
Definition
| To bind to a pathogen or toxin and quickly activate the complement cascade |
|
|
Term
| Why are IgA and IgG need to replace IgM as isotype switching and maturation progresses? |
|
Definition
| Pentameric IgM is large and doesn't penetrate infected tissues |
|
|
Term
| Receptor for IgG that helps transport the molecule across endothelial cells to the extracellular space? |
|
Definition
| FcRn or Brambell receptor |
|
|
Term
| What does FcRn protect IgG from? |
|
Definition
| The acidic nature of the endocytic vesicle |
|
|
Term
| The collective name for receptors that bind to the Fc portion of antibodies? |
|
Definition
|
|
Term
| What immunoglobulins are important in neutralizing blood-borne infections? |
|
Definition
|
|
Term
| What is the function of IgA? |
|
Definition
| Protects the surfaces of the mucosal epithelia that are exposed to external environments (GI tract, eyes, nose, throat, respiratory system, urinary, genital tracts, and mammary glands) |
|
|
Term
| A receptor on the basolateral surface of epithelial cells that transports dimeric IgA and to a lesser extent IgM across the epithelium to the apical surface where it is exposed to pathogen? |
|
Definition
|
|
Term
| Receptor mediated transport of the IgA or IgM molecules from one side of the cell to the other? |
|
Definition
|
|
Term
| What is the Poly-Ig receptor made up of? |
|
Definition
|
|
Term
| Small fragment of the Poly-Ig receptor that remains bound to dimeric IgA? |
|
Definition
|
|
Term
| What is the function of the secretory component? |
|
Definition
| Aids in holding dimeric IgA at the mucous membrane and preventing the molecules from being washed away |
|
|
Term
| What does IgE provide a mechanism for? |
|
Definition
| Rapid dejection of pathogens from the body |
|
|
Term
| What surface receptor found on mast cells, basophils, and eosinophils binds to IgE? |
|
Definition
|
|
Term
| When a molecule cross-links the IgE receptor, the mast cell secretes molecules that cause: |
|
Definition
| Sneezing, coughing, diarrhea, and vomiting |
|
|
Term
| What is IgE responsible for? |
|
Definition
| Allergy reactions and the binding of parasites and worms |
|
|
Term
| Which immunoglobulin is transported across the placenta directly into the fetal bloodstream? |
|
Definition
|
|
Term
| Which immunoglobulin can be transported in the breast milk and protects infants against mucosal pathogens? |
|
Definition
|
|
Term
| Transfer of one antibody or serum from one person into another? |
|
Definition
|
|
Term
| Age that an infact is most susceptible? Why? |
|
Definition
| 3-12 months because IgG slowly degrades as well as IgA once weaning begins |
|
|
Term
| High-affinity antibodies that bind to a pathogen and prevent the microbe's dissemination? |
|
Definition
|
|
Term
| Infects epithelial cells of the respiratory tract by binding to the oligosaccharides on their surface glycoproteins? |
|
Definition
|
|
Term
| Viral protein that is required for viral attachment? |
|
Definition
|
|
Term
| Bacterial surface proteins? |
|
Definition
|
|
Term
| Bind to cell surface receptors in the throat allowing the bacteria to grow and cause disease? |
|
Definition
|
|
Term
| What immunoglobulin binds to adhesion, preventing bacterial attachment? |
|
Definition
|
|
Term
| What antibodies are uses to neutralize microbial toxins and animal venom? |
|
Definition
| High-affinity IgG and IgA |
|
|
Term
| Binding of IgM and C1 protein to antigen on a pathogen's surface activates complement by what pathway? |
|
Definition
|
|
Term
| Most effective antibodies for activating complement? |
|
Definition
|
|
Term
| How can IgG molecules active complement? |
|
Definition
| Binding of 2+ IgG molecules or the binding of a toxin/broken down product of a pathogen |
|
|
Term
| What is the function of erythrocytes? |
|
Definition
| Oxygen transfer to tissues and clearing pathogens |
|
|
Term
| How do erythrocytes bind to pathogen? |
|
Definition
| C1 protein binds to C3b deposited on pathogen |
|
|
Term
| How do erythrocytes remove pathogens? |
|
Definition
| While circulating in the spleen in liver they transfer the pathogens to macrophages for phagocytosis |
|
|
Term
| Which antibody is the most flexible? |
|
Definition
|
|
Term
| T/F: The flexibility of the hinge region makes IgG susceptible to proteolytic cleavage? |
|
Definition
|
|
Term
| Which IgG subclass has the longest hinge region? |
|
Definition
|
|
Term
| Which IgG subclass is best at activating complement? |
|
Definition
|
|
Term
| Which IgG subclass does not activate complement? |
|
Definition
|
|
Term
| How is IgG4 different from other IgG subclasses? |
|
Definition
| It can exchange one of its heavy and light chains with other IgG4 molecules in circulation |
|
|
Term
| Differences in the constant regions of antibodies? |
|
Definition
|
|
Term
| Which IgG subclass has the most differences in constant regions? |
|
Definition
|
|
Term
| How many Gm allotypes does IgG4 have? |
|
Definition
|
|
Term
| Fc receptor specific for IgG with the main function of facilitating uptake and degradation of pathogens? |
|
Definition
|
|
Term
|
Definition
| Monocytes, macrophages, neutrophils, eosinophils, and DCs |
|
|
Term
| What is the function of FcγRII and FcγRIII? |
|
Definition
| Binding to IgG with lower affinity than FcγRI |
|
|
Term
| Antibody-dependent cell-mediated cytotoxicity (ADCC) |
|
Definition
| Mechanism by which natural killer (NK) cells recognize a cell or pathogen that has antibody bound to the target organism |
|
|
Term
| What antibody binds to high-affinity Fc receptors on mast cells, basophils, and activated eosinophils? |
|
Definition
|
|
Term
| Molecule in the cytoplasm that contributes to inflammation? |
|
Definition
| Histamine (inflammatory mediator) |
|
|
Term
| How do activated granular cells directly attack a pathogen? |
|
Definition
| By secreting their effector molecules |
|
|
Term
| T/F: The Fc receptor for monomeric IgA belongs to a different family from the Fc receptors for IgG and IgE. |
|
Definition
|
|
Term
| What else can Fc receptors bind to other than molecules? |
|
Definition
| C reactive proteins that have coated bacteria leading to phagocytosis and degradation of the pathogen |
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