USMLE: immunology Flashcards

cells
Terms Definitions
ANA
SLE
grave's
HLA B8
anti-Scl-70
scleroderma (diffuse)
Antihistone
Drug-induced lupus
anti-Ro/anti-SS-A
Sjogren's syndrome
anti-gliadin, andi-endomysial
Celiac antibodies
antinuclear antibodies (ANA)
SLE
Anti-IgG
Rheumatoid factor/rheumatoid arthritis
HLA A3
primary hemochromatosis
C5-C8
deficiency => neisseria bacteremia
anti-dsDNA, anti-Smith
specific for SLE
Ig's that activate ADCC
IgG
MHC 2 genes:
HLA-DP, HLA-DQ, HLA-DR
steroid responsive nephrotic syndrome
HLA DR7
these communicate with efferent lymphatics and contain reticular cells and macrophages
medulla
Type of hypersensitivity: ITP
Type II
Wiskot-Aldrich syndrome
X-linked recessive. "WIPE": recurrent infections, thrombocytopenic purpura, eczema, risk of lymphomas, low IgM
these communicate with efferent lymphatics and contain reticular cells and macrophages
medulla
rheumatoid factor and anti-SS-A
Sjogren syndrome
Organisms expressing MHC 1:
All multicellular organisms
what instructs macrophages to become epitheliod and multinucleated giant cells?
interferon-gamma
What are defined by Ag-binding specificity?
Idiotypes
What Ig activates the alternate pathway, neutralizes bacterial endotoxins and viruses, and prevents bacterial adherence?
IgA
What type II hypersensitivity disorder is defined as• Autoantibodies directed against the TSH receptor?
Graves disease
Name the B-cell CD marker:• Required for class switching signals from T cells
CD40
IL-2
Secreted by TH cells. Induces proliferation and enhances activity of TH and CTLs
Type of hypersensitivity: hemolytic anemia
Type II
Type of hypersensitivity: Rheumatoid arthritis
Type III
autoimmune hemolytic anemia, Rh disease, Goodpasture's, rheumatic fever, Grave's disease, bullous pemphigoid, MG, and ITP are all examples of what type of hypersensitivity?
type II
HLA DR5
pernicious anemia & juvenile RA
complement proteins involved in anaphylaxis
C3a, C5a
Name the B-cell CD marker:
• Required for class switching signals from T cells
CD40
Which leukotriene is chemotactic for neutrophils?
LTB4
this Ig epitope is determined by antigen-binding site; specific for a given antigen
idiotype
this Ig type prevents attachment of bacteria and viruses to mucous membranes, does not fix complement
IgA
this immune deficiency is associated with congenital defects of heart and great vessels
DiGeorge syndrome
in this type of hypersensitivity, antigen-antibody complexes activate complement, which attracts neutrophils; neutrophils release lysosomal enzymes
type III
What complement factor deficiency leads to• Hereditary angioedema?
C1 inhibitor (C1-INH)
What Ig is the major protective factor in colostrum?
IgA
What is the term for different classes and subclasses of the same gene products?
Isotypes
Antibodies that can activate the classic complement
IgG, IgM
Type of hypersensitivity: Graft Vs. Host
Type IV
CD16
Fc receptor on NK cells, macrophages, neutrophils. IgG-mediated opsonization and ADCC
CD18
β chain of LFA-1 integrin on leukocytes. Cell adhesion molecule missing in LAD
what does Th cell secrete that activates Tc cell to kill virus-infected cell?
IL-2
this syndrome is associated with elevated IgA levels, normal IgE levels, and low IgM levels
Wiskott-Aldrich syndrome
this Ig has the lowest concentration in serum
IgE
defect in DNA repair enzymes with associated IgA deficiency; presents with cerebellar problems and spider angiomas
ataxia-telangiectasia
What complement factor deficiency leads to
• Hereditary angioedema?
C1 inhibitor (C1-INH)
Which IL is associated with increases of IgG and IgE?
IL-4
What complement factor or factors are associated with
• Membrane attack complex (MAC)?
C5–C9
IL12-R deficiency; decreased TH1 response
decreased IFNy; disseminated mycobacterial infxn. defect?
what drains everything but the right arm and right half of head?
thoracic duct
what does IL-12 receptor deficiency (decreased activation of T cells) present with?
disseminated mycobacterial infections
what type of cells are responsible for graft and tumor rejection and regulation of antibody response?
T cells
this type of immunity is based on receiving preformed antibodies from another host
passive
What cytokine do Th1 cells secrete to inhibit Th2 cell function?
INF-gamma
Name the type of graft described by these transplants: Between genetically identical individuals
Isograft
What immunologic test checks for a reaction between Abs and a particular Ag? (hint: ABO typing)
Agglutination test
ELISA test
The particular antigen is coated onto microplates and serum from the patient is added followed by addition of enzyme-labeled antihuman Ig. A chromogenic substrate for the enzyme is then added which produces color if positive. Very sensitive. Used for the HIV p24 antigen as well as many hormones, antibiotics, proteins infectious antigens and tumor markers.
Characteristics of IgA
Inhibits binding of antigens to mucosal surfaces; exists as a dimer; secreted in breast milk; does not activate complement or act as opsonin
what is the site of B cell localization and proliferation?
follicle
what drains everything but the right arm and right half of head?
thoracic duct
what types of hypersensitivity are antibody-mediated?
I, II, III
What type II hypersensitivity disorder is defined as
• Autoantibodies directed against RBC Ag I?
Autoimmune hemolytic anemia
What immunologic test checks for a reaction between Abs and a particular Ag? (hint: ABO typing)
Agglutination test
What cell surface marker is found on activated helper T cells?
CD40
these are long, vascular channels in red pulp with fenestrated "barrel hoop" basement membrane
sinusoids of spleen
this type of Ig epitope differs among members among members of same species; can be on light chain or heavy chain
allotype (polymorphism)
what part of the thymus is dense with immature T cells?
cortex
What is the only Ig that crosses the placenta?
IgG
What is the major Ig of the secondary immune response in the mucosal barriers?
IgA
Pathophysiology of CGD
Deficiency of NADPH oxidase with no production of superoxide radical and H2O2 which is the substrate for myeloperoxidase to produce bleach. In catalase(-) infections myeloperoxidase uses H2O2 produced by the bacteria. If it's catalase(+), H2O2 is degraded by the bacterial catalase and theres insuficient respiratory burst response to kill Staph, pseudomona, serratia, aspergillus. Dx.: with negative nitroblue tetrazolium test
Pathophysiology of lepromatous leprosy
Strong TH2 response inhibits TH1 cell-mediated immunity. IL-4 and IL-5 activate B cells with production of humoral antibodies that are insuficient to erradicate the infection. Severe tissue damage and disfiguration.
Characteristics of eosinophils
Found in the bloodstream, have bilobed nucleus with large pink granules
Universal blood donor
Type O. These individuals will have anti-A and anti-B IgM antibodies and therefore can only accept O blood.
interferons induce the production of a 2nd protein that inhibits viral protein synthesis by doing what?
degrading viral mRNA
these are long, vascular channels in red pulp with fenestrated "barrel hoop" basement membrane
sinusoids of spleen
What subset of CD4 T cells is responsible for mast cell and eosinophil precursor proliferation?
Th2 cells
What is the only Ig that crosses the placenta?
IgG
leukocyte adhesion deficiency type 1. CD18 (LFA-1 integrin protein)
neutrophilia. no pus formation. delayed separation of umbilicus. defect?
this syndrome is characterized by an X-linked defect in the ability to mount an IgM response to capsular polysaccharides of bacteria
Wiskott-Aldrich syndrome (decreased activation of B cells)
what is the most specific marker for NK cells?
CD56; also CD16
What is the first human disease successfully treated with gene therapy?
Adenosine deaminase (ADA) deficiency
What AR disorder is seen by age 1 to 2 with recurrent sinopulmonary infections, uncoordinated muscle movements, and dilation of the blood vessels?
Ataxia-telangiectasia
site of immature thymocytes in the thymus
cortex; CD3+, CD4+, CD8+
Flow cytometry test
Analyzes and sorts cell types from a complex mixture. Fluorescent antibodies of different colors agasint cell surface markers bind to different cell types and are detected by a machine that plots a histogram with the x-axis for one dye and the y-axis for the other. Therefore cells that are CD3+ and CD8+ will be plotted on the top right quadrant.
Where are Tdt+ T cells found
bone marrow and thymic pre-cortex
helper T cells have ____, which binds to ____ on antigen-presenting cells
CD4; MHC II
what part of the thymus is pale with mature T cells and epithelial reticular cells?
medulla (M-mature/medulla)
What is the term to describe the limited portion of an Ag that is recognized by an Ab?
Antigenic determinant (epitope)
Cell type in lymph node follicles
B-cells: naive B-cells in primary follicle, effector B-cells in Germinal Centers
cell surface proteins on NK cells
receptors for MHC I, CD 16
What are the five Ig isotypes?
IgA, IgD, IgE, IgG, and IgM
processes responsible for idiotype diversity
1) gene rearrangements at the DNA level; 2) alternative splicing to isotype at RNA level
CTL costimulatory molecules
CD28 on CTLs bind B7 on APCs. IL-2 produced by TH1 cells stimulate CTL differentiation
Costimulatory molecules on T cells
LFA-1, CD2, CD28. Bind ICAM-1, LFA-3 and B7 on macrophages respectively
how is antibody diversity generated?
1. random recombination of VJ (light chain) or VDJ (heavy chain) genes 2. random combination of heavy chains with light chains 3. somatic hypermutation 4. addition of nucleotides to DNA during genetic recombination by tdt
cell surface proteins on NK cells
receptors for MHC I, CD 16
What test is done to diagnose CGD?
Nitroblue tetrazolium reduction test (NBT). It is negative in patients with CGD because there is no production of oxygen radicals.
Where are B cells found in the spleen?
Follicles in the white pulp
cell surface proteins on B cells
IgM, B7, CD19, CD20, CD40, MHC II
Which region of the variable domain comprises the Ag-binding site of the Ab?
Hypervariable region (three per light chain; three per heavy chain)
What is the term for the strength of the association between Ag and an Ab?
Affinity (one of each)
What is VJ recombination
It’s the process by which the B cell light chain gene's (and T cell α chain gene's) V and J segments are randomly recombined and spliced to form a unique N terminal sequence or idiotype on the B and T cell receptors
defect in CD40 ligand on CD4 T helper cells leads to inability to class switch; presents early in life with severe pyogenic infections
hyper-IgM syndrome (decreased activation of B cells)
What are the two opsonizing factors?
The Fc region of IgG and C3b
the classic pathway is activated by what?
IgG or IgM (GM makes classic cars)
True or false? T cells can recognize, bind, and internalize unprocessed Ags.
False. B cells recognize unprocessed Ags, but T cells can recognize only processed Ags.
Costimulatory molecules on B cells
CD40 and B7, bind CD40L and CD28 on TH2 cells
the classic pathway is activated by what?
IgG or IgM (GM makes classic cars)
What is the most common precipitin test used in clinical medicine?
Radial Immuno Diffusion (RID) for Ig levels.
SCID; IL2-R; x-linked. MC type of SCID
normal B cells, no T cell activation. recurrent fungal, bacterial, and protozoal infections. defect? genetics
What are the four chemotactic agents?
1. C5a
2. Leukotriene B4
3. IL-8
4. Bacterial peptides
What IL do T cells secrete to induce T-and B-cell division?
IL-2. T cells express IL-2 receptors on their surface to induce self-expression.
What MHC class of antigens do all nucleated cells carry on their surface membranes?
MHC class I antigens; they are also found on the surface of platelets.
What would be the result if an Ab were cleaved with pepsin?
There would be a Fab' region; thus, it would still be able to participate in precipitation and agglutination.
What would be the result if an Ab were cleaved with papain?
There would be two Fab and Fc regions.
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