Term
| Antibodies are the excreted proteins more generally known as __________? |
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Definition
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Term
| What are the 5 isotypes of constant region heavy chain and the 2 isotypes of light chain? |
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Definition
| IgA, IgD, IgE, IgG, IgM; kappa and lambda. |
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Term
| True or False: Since the immunoglobin genes are inherited through germ line configurations, they are also expressed in those same configurations. |
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Definition
| False, they are not expressed that way. |
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Term
| Which region of the immunoglobin chain is made first? |
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Definition
| Variable region of both light and heavy chains |
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Term
| In regards to gene arrangement in Ig’s, a light chain joins a V and J segment and the heavy chain joins the J and D to the V segment, is this correct? |
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Definition
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Term
| What is somatic recombination and the enzymes it uses? |
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Definition
| It is the process that splices genes various regions of immunoglobin genes together utilizing Rag 1&2 enzymes to enhance genetic variety. |
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Term
| What are the first Ig’s that naïve B cells can express on their surfaces and are the only ones that can be produced simultaneously by a B cell? |
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Definition
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Term
| Since Ig molecules on the surface of B cells can't communicate to the cell interior what additional proteins make the process fully functional? |
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Definition
| Surrounding the Ig with Ig-alpha and Ig-beta proteins with long cytoplasmic tails |
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Term
| Describe what happens to the following immature B-cells when: it expresses receptors for multi-valent self-antigens, expresses weaker self-antigen receptors, or has no self reaction. |
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Definition
| 1- They are deleted from immune system via apoptosis, 2- it forms a anergic B-cell capable of producing auto-antibodies in peripheral tissues, 3- forms a marture B-cell in peripheral tissues. |
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Term
| What is allelic exclusion? |
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Definition
| Despite the B-cell having two copies of the each gene, this process allows the production of monoclonal antibodies. |
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Term
| What type of antibodies are used in serological assays, diagnostic probes, therapeutic agents? |
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Definition
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Term
| What initiates the process of a naïve B cell proliferating and differentiating and the synthesis of IgA, IgG, IgE? |
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Definition
| Binding of antigen for the first time. |
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Term
| Once the appropriate signals are given to the B-cell for antibodies to be made what 3 important things occur? |
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Definition
| Secreted antibodies, somatic hypermutation, and isotype swithching. |
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Term
| How are somatic hypermutation and affinity maturation related? |
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Definition
| Somatic hypermutation described how mutations accumulate in the variable regions of the antibody molecule, while the process that selects those mutants that bind the antigens with the greatest affinity are allowed to proliferate is called affinity maturation. |
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Term
| What is the necessity for isotype switching in antibody creation? |
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Definition
| Because it allows the variable regions of antibodies to utilize the different effector functions of the other isotypes. |
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Term
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Definition
| The part of the macromolecule that an antibody binds to. |
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Term
| The presence of what immunoglobin is effective in diagnosing recent infections? |
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Definition
| IgM, which is present for approx. 6 weeks |
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Term
| List the main features of IgM and IgD. |
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Definition
| IgM- first antibody produced, activates complement cascade, present on naïve B-cells; IgD- main role as a membrane receptor on B-cell, also active in naïve B-cells |
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Term
| List the main features of IgA, IgG, and IgE. |
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Definition
| IgA- most made of any isotype despite not reaching serum, important in mucosal immunity in the GI/nose/lung, crossing epithelium; IgG- inactivates toxins, opsonize bacteria, activate complement, neutralize viruses/bacteria, crosses the placenta, most abundant antibody in internal fluids; IgE- fight parasites and worms, cause allergic responses by activating mast cells. |
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Term
| What is the key difference in antigen binding in T-cell receptors versus Ig receptors? |
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Definition
| T-cell receptors only recognize peptide antigens that are bound to MHC molecules and doesn’t have class switching/somatic hypermutation, whereas Ig receptors can bind to many epitopes and can do those things. |
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Term
| True or False: T cell receptors are rarely membrane bound, have somatic mutations after stimulation, can become soluble once stimulated. |
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Definition
| False, always membrane bound, no mutations once antigen has bound, never soluble. |
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Term
| What is the process called where antigen is degraded to a peptide:MHC complex for recognition outside the cell? |
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Definition
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Term
| What are the 3 antigen presenting cells? |
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Definition
| Dendritic cells, Macrophages, B-cells. |
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Term
| Briefly describe the T-cell response to antigen from extracellular pathogens. |
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Definition
| Extracellular pathogen, APC (antigen presenting cells) present MHC-II, induce Helper T Cells CD4-Th2, antibody creation |
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Term
| Briefly describe the T-cell response to antigen from intracellular bacteria or fungus. |
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Definition
| Pathogen’s antigen presented by APC’s as MHC-II, induce T-cell CD4-Th1, activate macrophages and upregulate lysosomes |
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Term
| Briefly describe the T-cell response to antigen from viral infected cells. |
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Definition
| Viral infection, MHC-I presentation, induce T-cells to CD8 Cytotoxic, identification and killing of viral infected cells |
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Term
| If the T-cells that bind to MHC-I or II with self-antigen are quickly deleted, how do T-cells still contribute to autoimmunity? |
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Definition
| Sometimes the MHC is not bound avidly enough to present the antigen and therefore those T-cells may not be eliminated. Later these T-cells may be activated to cause disease. |
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Term
| True or False: Staph endotoxins and the toxic shock syndrome toxin function as antigens. |
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Definition
| False, they are superantigens which stimulate a massive generalized immune response which are systemically toxic and suppress the adaptive response. |
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Term
| What are the two signal required to induce a B-cell to a plasma cell? |
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Definition
| Two complexes on the CD4-Th2 cell induce it, TCR-MHC-II and B7-CD28. |
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Term
| What is the site for T-cell maturation? |
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Definition
| Thymus and thymic stroma, some can develop in intestine |
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Term
| True or False: The major histocompatibility complex is completely different from the HLA, human leukocyte antigen. |
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Definition
| False, the HLA is the variable component of the MHC. |
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Term
| True or False: The genes that encode the MHC-I/II molecules rearrange and undergo developmental changes just like Ig’s. |
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Definition
| False, they do not rearrange or undergo changes, diversity is obtained because of unique expression |
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Term
| Name the MHC Class I genes and recite how many class I genes a given individual might express. |
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Definition
| HLA-A,B,C and a person expresses 6 genes, two from each type |
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Term
| Name the MHC Class II genes and recite how many genes are expressed on a cell surface. |
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Definition
| HLA-DP,DQ,DR, with varying alpha and beta chain alleles, but a person normally expresses 6 genes, two from each group |
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Term
| True or False: The MHC is both polygenic AND polymorphic. |
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Definition
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Term
| If the association of antigenic peptides and MHC molecules is a low affinity interaction then how can the complex work? |
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Definition
| The low affinity indicates a slow on rate and off rate, so once the complex forms it stays bound for weeks to be recognized by T-cell receptors |
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Term
| Can multiple different peptides bind to the same MHC molecule? |
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Definition
| Yes, but one at a time, this is unlike highly specific antibodies |
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Term
| What types of cells express MHC-I and MHC-II? |
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Definition
| MHC-I are expressed on almost all cells with a nucleus, MHC-II are expressed on professional antigen presenting cells macros/B-cells/dendtritic |
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Term
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Definition
| Each TCR is specific to not just the antigen but the MHC component, so each TCR recognizes 1 out of 12 MHC proteins |
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Term
| Why are transplant patients given cyclosporine? |
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Definition
| To prevent the upregulation of IL-2 and inhibit T-cell production. |
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Term
| True or False: Mature B-cells can respond to bacteria polysaccharides without the need for T-cell antigen. |
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Definition
| True, they are called thymus-indepent 2 antigens. |
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Term
| What is a conjugate vaccine? |
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Definition
| Antigen is bound to a carrier protein that is ingested by a naïve B-cell, the components are presented to T-cells via MHC-II, the T-cells then activate the B-cell to become mature and provide protection against the antigen. |
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Term
| What is hypersensitivity, autoimmunity, immunodeficiency? |
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Definition
| Too much immunity to foreign antigen; too much for self; to little for foreign |
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Term
| What are the 4 types of immune responses/hypersensitivity reaction? |
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Definition
| I- Allergy and Anaphlyaxis, II- antibody mediated, III- antibody-antigen complex mediated, IV- Cell mediated(T-lymphocytes) |
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Term
| What are the different body reactions to Type I Hypersensitivity of subcutaneous allergens, intravenous allergens, inhaled allergens? |
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Definition
| Local release of histamine with wheal and flare; general release of histamine, anaphlyaxis; allergic rhinitis and asthma due to contraction of bronchial smooth muscle |
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Term
| What is the proposed hypothetical benefit to the release of IgE in hypersensitivity I reactions? |
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Definition
| Possible parasite fighter |
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Term
| Briefly describe the process of a hypersensitivity I reaction. |
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Definition
| Allergy antigen induces CD4-Th2 to signal B-cells via IL-4 to create antibodies IgE, IgE binds to mast cells and basophils, second exposure to allergen, mast/basophil cells release inflammatory granules |
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Term
| Briefly describe the process of a hypersensitivity II reaction. |
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Definition
| IgG or IgM antibody coats cell surfaces or ECM, induces complement system for either opsonization or C5-C9 cell lysis |
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Term
| True or False: An ABO blood type mismatch can cause a type 2 hypersensitivity reaction inducing red blood cell destruction. |
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Definition
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Term
| Briefly describe the process of hypersensitivity III reaction. |
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Definition
| IgG antibody forms complex with antigen(endo/exogenous), induces complement C3a/4a/5a inflammatory mediators and mast cell degranulation, local inflammation occurs with phagocytosis and blood vessel occlusion |
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Term
| True or False: Since Type III hypersensitivity gives rise to local or systemic disease the following diseases are all associated with type III - glomerulonephritis, rheumatoid arthritis, systemic lupus erythematosus, serum sickness. |
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Definition
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Term
| Of the 5-year survival rates for organ transplant which of these is different from all the others in that it is lower than 70%: kidney, liver, heart, bone marrow, lung, cornea? |
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Definition
| Lung has the lowest survival rate of organ transplants. |
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Term
| In organ transplant, you can never get a complete HLA match from the donor except in which case? |
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Definition
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Term
| Which types of hypersensitivity are involved in organ transplant rejection? |
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Definition
| Type II, III, IV (CD4 and CD8) |
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Term
| Briefly describe the process of type IV hypersensitivity in both the delayed type and cell mediated type. |
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Definition
| Delayed - CD4-Th1 cells see MHC-II, release cytokines causing vasodilation/inflammation and recruit monocytes, and may form a granuloma; Cell-mediated - CD8 cells see MHC-I on virus-infected cells, tumors, transplants and induce apoptosis. |
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Term
| What is the difference between central and peripheral tolerance in immunity? |
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Definition
| Central is the development of tolerance during development and peripheral occurs out in tissues after antigen encounter. |
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Term
| What are the 4 mechanisms of tolerance and what do they involve? |
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Definition
| Clonal deletion- removes autoreactive B/T cells by apoptosis during maturation and in the periphery following immune response; Clonal Anergy- cell are alive but turned off, T-cells see Ag without B7/CD28, B-cells lose surface immunoglobin expression; Peripheral suppression- dendritic/CD4/CD8 cells suppress immune response by contact or cytokines; Immunologic ignorance- low antigen density so threshold for response not achieved |
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Term
| True or False: Autoimmune diseases occur in every organ but it is rarely due to a failure of tolerance mechanisms. |
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Definition
| False, occurs in most organs and it is due to usually do to failure of tolerance. |
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Term
| What is the most common cause of immunologic disease in regards to tolerance mechanisms? |
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Definition
| Failure in immune ignorance |
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Term
| Describe the four mechanisms causing immune ignorance to fail- creation of new epitopes, molecular mimicry, polyclonal lymphocyte activation, exposure to immune privileged sequestered antigen. |
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Definition
| 1-drugs/microbes attach to self-antigens(haptens) or molecular degradation exposes cryptic self-antigens; 2- infectious agent has antigen that resembles self, so cross-reacting antibodies now recognize self-antigen; 3- occurs when APCs or bacterial LPS or virus overcomes anergic cell with stimulation causing proliferation; 4- since these antigens were not seen by lymphocytes during development they will be recognized as foreign(antigen from brain, lens, testes, inside of cell) |
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Term
| What perturbs an immune system to trigger development of autoimmune disease? |
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Definition
| Trauma, infection, puberty |
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Term
| What is the difference between primary and secondary immunodeficiency? |
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Definition
| Primary is the result of a specific genetic deficiency affecting the development/function of immunity versus secondary which is the result of an acquired condition that suppresses or destroys the immune system. |
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Term
| True or False: The following agents can cause primary immunodeficiency - infections, malnutrition, aging, side effect of chemo, aids. |
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Definition
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Term
| True or False: The phenotype for T-cell defects are viral/fungal infections and no granuloma formation. |
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Definition
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Term
| True or False: the phenotype for B-cell defects are recurrent bacterial infections due to inability to oposonize and susceptibility to some parasites. |
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Definition
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Term
| What percentage of immunity is needed for herd immunity? |
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Definition
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Term
| What are the top 3 targets for vaccination? |
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Definition
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Term
| Regardless of the mechanism of HIV, loss of which cell type is the cause of immune failure and eventually AIDS? |
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Definition
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Term
| Elaborate on the concept of “set point” for viremia. |
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Definition
| There is a correlation between CD8 Tcells onset/decline with viremia reduction/rise over time; in the asymptomatic phase, while CD8 and virus equilibriate, there is a set point maintaining the level of viral load at a certain amount in the blood. The higher the setpoint the quicker the onset of disease progression at the end of the asymptomatic phase. |
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Term
| What are the 4 different factors of HIV infection that cause the failure of the CD8 Tcells? |
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Definition
| Loss of CD4 help because HIV kills active CD4’s, viral Nef protein downregs MHC class I expression on cells, ability of HIV-I to mutate changing its epitope, clonal exhaustion of CD8 progenitors |
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Term
| True or False: The key reasons that antibody responses fail in HIV-1 is because of conformational masking and extensive glycosylation of the virus membrane making antibody binding difficult. |
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Definition
| True, it is also due to viral escape mutation in the epitope and the general dysfunction of B cells due to the lack of CD4-Th2’s to induce them. |
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Term
| Elaborate on the structure of an antibody. |
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Definition
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Term
| Elaborate on the process of antibody cleavage considering that fragments are still antigen binding. |
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Definition
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Term
| Elaborate on the difference between antibody and T cell receptor structure. |
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Definition
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Term
| Elaborate on the structure of the T cell receptor complex. |
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Definition
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Term
| These are the most important IL molecules, their source, and their target. |
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Definition
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