USMLE Immunology First Aid – Flashcards
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This part of the lymph node is underdeveloped in patients with DiGeorge syndrome. T cells occupy this portion.
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Parcortex
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What is the site of B cell proliferation within the lymph node?
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Follicle
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Splenic dysfunction is associated with the invasion of wich organisms?
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SHiN SKiS (Salmonella, Haemophilus influenzae type B, N. meningiditis, S. pneumoniae, Klebsiella, Group B Strep)
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What are the kind of cells found in patients postsplenectomy?
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Target cells, Howell-Jolly bodies
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What is the embryologic origin of the thymus?
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3rd branchial pouches
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Wich are the HLA types associated with MHC I?
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HLA-A, HLA-B, HLA-C
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Wich are the HLA types associated with MHC II?
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HLA-DP, HLA-DQ, HLA-DR
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What disease is associated with HLA-A3?
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Hemochromatosis
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Wich deseases are associated with HLA-B27?
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Rheumatoid Arthritis, Psoriasis, Ankylosing spondylitis, Inflammatory Bowel Disease, Reiter's syndrome
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Wich diseases are associated with HLA-DR2?
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Multiple sclerosis, hay fever, SLE, Goodpasture's
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Wich diseases are associated with HLA-DR3?
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Diabetes mellitus type I, Grave's diseases
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Wich diseases are associated with HLA-DR4?
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Rheumatoid arthritis, Diabetes mellitus type I
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Wich diseases are associated with HLA-DR5?
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Pernicious anemia, Hashimoto's thyroditis
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The process in wich T cells expressing T-Cell Receptors capable of binding surface self MHC molecules survive, is called:
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Positive selection
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The process in wich T cells expressing T-Cell Receptors with high affinity for self antigens undergo apoptosis is called:
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Negative selection
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The cell surface markers that function as co-stimulatory signals between the T CD4+ cell and the APC are:
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B7 and CD28
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What are the contents of the granules released by Cytotoxic T cells in response to virus-infected, neoplastic or donor graft cells?
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Perforin, Granzyme, Granulysin
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This portion of the antibody structure determines the isotype (IgM, IgD, etc):
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Fc (constant region)
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What are the forms in wich antibodies act against organisms?
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Opsonization, Neutralization and Complement activation
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This immunoglobulin isotype crosses the placenta and is the most abundant Ig in blood.
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IgG
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This immunoglobulin isotype can be found as a monomer or dimer, it is found in secretions such as tears, saliva, mucus and breast milk.
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IgA
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This immunoglobulin isotype is produce in the inmediate response to an antigen. It can be either a monomer or a pentamer and it fixes complement but does not cross the placenta.
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IgM
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This immunoglobulin isotype is related to mast cells, basophils and eosinophils. It mediates type I hypersensitivity
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IgE
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What is the difference between Thymus-independent antigens and Thymus-dependent antigens?
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Thymus-independent antigens lack a peptide component and therefore cannot be presented by MHC to T cells (lipopolysaccharide from cell envelope of gram-negative bacteria) and they only induce IgM. Thymus-depent antigens contain a protein component and they induce class-switching and form immunologic memory
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Wich are the complement proteins associated with anaphylaxis?
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C3a, C5a
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What is the function of C3b?
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Binds bacteria (Opsonization)
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What is the complement protein associated with neutrophil chemotaxis?
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C5a
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Wich complement proteins form the Membrane Attack Complex (MAC)?
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C5b-C9
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Hereditary angioedema is caused by:
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Deficiency of C1 esterase
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Severe, recurrent pyogenic sinus and respiratory tract infections; increased susceptibility to type III hypersensitivity reactions are dure to:
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Deficiency of C3
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Neisseria bacteremia can be caused by a deficiency of wich complement proteins?
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C5-C8
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Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a deficiency of:
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DAF
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What are the functions of IL-1 and IL-6?
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Endogenous pyrogens. Causes fever and acute inflamation
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What is the function of IL-8?
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Major chemotactic factor for neutrophils
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What is the function of IL-12?
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Induces differentiation of T cells into Th1 cells.
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This cytokine mediates septic shock and activates endothelium:
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TNF-Alpha
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What is the cytokine that activates macrophages?
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IFN-y
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What is the function of IL-4?
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Induces differentiation of T cells into Th2 cells. Enhaces class swtiching to IgE and IgG
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This cytokine promotes differentation of B cells. It enhaces class switching to IgA. It also stimulates the growth and differentiation of eosinophils.
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IL-5
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What is the function of IL-10?
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Inhibits actions of activated T cells.
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What is the function of alpha and beta interferons?
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Inhibit viral protein synthesis
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How does interferon-y act to interfere with viruses?
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Increases MHC I and II expression and antigen presentation in all cells.
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Epstein-Barr virus is associated with wich B cell surface protein?
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CD21
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The process in wich self-reactive T cells become nonreactive without costimulatory molecule is known as:
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Anergy
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What is the difference between Active and Passive immunity?
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Active immunity is induced after exposure to foreign antigens, has a slow onset and creates memory. Passive immunity is based on receiving preformed antibodies from another host, has a rapid onset and doesn't create memory
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Measles, Mumps, Rubella and Polio (Sabin) are examples of what kind of vaccine?
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Live attenuated
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Polio (Salk), Hep B, Cholera, Rabies
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Killed or inactivated
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Anaphylatic and atopic; free antigen cross-links IgE on presensitized mast cells and basophils, triggering release of vasoactive amines that act on postcapillary venules.
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Type I hypersensitivity
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Antibody mediated; IgM, IgG bind to fixed antigen on enemy cell. It is tested for using direct and indirect Coombs.
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Type II hypersensitivity
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Immune complex formation. Serum sickness and Arthus reaction are examples of it.
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Type III hypersensitivity
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What is the clinical presentation of Serum Sickness?
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Fever, arthralgia, urticaria, proteinuria, lumphadenopathy, 5-10 days after antigen exposure.
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Delayed (T-cell mediated) type; sensitized T lymphocytes encounter antigen and then release lymphokines..
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Type IV hypersensitivity
