Immunologic Mechanisms Flashcards
what is a hapten
small molecule antigen requiring covalent linkage to a larger carrier to stimulate an immune response
What is the receptor for IL2?
CD25
what is a carrier protein
macromolecule to which a hapten is bound
what is an adjuvent
molecules that enhance the immune response
what is a superantigen
antigens that activate a large number of polyclonal T cells (bacterial toxin)
what are anchor residues
peptide side chains that bind in the peptide-binding cleft of MHC
Mutation for TAP (transports antigent to ER)
produces bare lymphocyte syndrome
deficiency of MHC class I or II causes what disease?
Bare lymphocyte syndrome
what is anergy
state of unresponsiveness to antigenic stimulation – weak signal, lack of costimulation
what is tolerance
unresponsiveness to antigen
what are tolerogens
antigens that induce tolerance
Tregs express these cellular markers
CD4, CD25 and FoxP3
what happens in those with an AIRE gene mutation
lymphocytes are not deleted or tolerized to endocrine related self-antigen. Causes APS
Tolerance is maintained by secretion of what
IL-10 and TGFβ
FoxP3 mutation leads to this disease
IPEX (immune dysregulation, polyendocrinopathy, enteropathy X-linked) syndrome
Characteristics of IPEX
watery diarrhea, eczema, endocrinopathy, immune dysregulation
what is the mutation in ALPS (autoimmune lymphoproliferative syndrome)
FAS or caspase 10
Characteristics of ALPS
lack of tolerance leads to autoimmunity; lymphocytes don’t die
Which IgG subclass has the shortest half life
IgG3
what is rheumatiod factor
antibody against Fc portion of IgG. Typically IgM
Which immunoglobulin fixes complement most efficiently
IgM
Somatic hypermutation leads to changes in what
variable region, not constant region
Class switching leads to changes in what
constant region, not variable region
How does alternative splicing change Ig
changes from transmembrane to secretary form
XLPS (X-linked lymphoproliferative syndrome) is due to a mutation in what
SAP (SLAM-associated protein)
Which TLR binds LPS
TLR4
Which TLRs are present in the intracellular compartment and implicated in HSV1 encephalitis
TLR 3, 7, 8, 9
Cyclosporine inhibits calcineurin and blocks NFAT activation by binding to what
cyclophilin
Gene 17q12-21 codes for
ORMDL3 - SNPs = increased asthma risk
Gene 5q22-32 codes for
CD14; LPS receptor - SNPs = increased and decreased risk of asthma and atopy
Gene 3p21-22 codes for
CCR5 chemokine receptor - SNPs = protection against non-atopic asthma
Gene Xp22 codes for
TLR 7 and 8 - SNPs = increased risk of all atopic disease
Gene 5q31 codes for
IL-13; SNP = increased risk of asthma, linked to response to montelukast
Gene ADRB2 codes for
Beta2-adrenergic receptor - SNP = decreased response to albuterol
Gene ADAM33 codes for
Type 1 Transmembrane protein - SNP = increased risk of asthma
Cytokines inducing IgG1 production; IgG1 fxn
IFNγ, IL-4; opsonization & complement fixation
Cytokines inducing IgG2 production; IgG2 fxn
IFNγ, TGFβ; Antipolysaccharide antibody
Cytokines inducing IgG3 production; IgG3 fxn
IFNγ; opsonization & complement fixation
Cytokines inducing IgG4 production; IgG4 fxn
IL-4, IL-13; Antipolysaccharide antibody
Cytokines inducing IgA production; IgA fxn
TGFβ, IL-5; mucosal immunity (IgA1 serum and respiratory, IgA2 GI)
IgM fxn
complement fixation; primary response
Cytokines inducing IgE production; IgE fxn
IL-4, IL-13; allergic response
Receptors on T cells for B7-1 (CD80) and B7-2 (CD86) and effect
CD28 (activation of naive cells) and CTLA4 (CD152 - tolerance)
Receptors on T cells for ICOS-L and effect
ICOS - costimulation of effector T cells
Receptors on T cells for CD40 and effect
CD40L - APC activation, germinal center dev., class switching
Receptors on T cells for PD-L1/PD-L2 and effect
PD-1 - negative regulation, cell death
NKT cells recognize what type of antigen, presented on what?
lipids on CD1
What is the function of Lck
T cell receptor signaling (tyrosine kinase) associated with CD4/CD8
Function of SAP (SLAM-associated protein)
Links SLAM to Fyn in T-cell signaling
What is the function of Fyn
T cell receptor signaling (tyrosine kinase) associated with CD3
binding sites for TCR on MHC I and II, respectively
α3 and β2
where are antigens loaded onto MHC class I?
endoplasmic reticulum
where are antigens loaded onto MHC class II?
Phagolysosome
which molecules are part of the Ig superfamily?
TCR, MHC, CD4, CD8, CD19, B7-1, B7-2, Fc receptors, KIR, VCAM-1
which Ig class has the highest total body concentration?
IgA
ZAP-70 deficiency results in what
T-, B+, NK+ SCID with no CD8 cells
CD21 on B cell function
enhances BCR signal by binding C3d
what are the CD molecules that make up the BCR complex?
CD21, CD19, CD81
function of IL-12
promotes differentiation of CD4 into TH1
function of IL-15
survival f memory CD8 T cells, NK cells and NK-T cells
function of IL-23
promotes differentiation and maintenance of T cells that product IL-17
function of TGFβ
inhibits T cell proliferation and effector functions
which chemokine receptor is associated with WHIM (warts, hypogam, infxn, myelokathexis) syndrome
CXCR4
Receptor for CCL5 (RANTES)
CCR 1,3,5
receptor for CCL11 (eotaxin)
CCR3
Receptor for CCL17 (TARC)
CCR4
Receptor for CXCL8 (IL-8)
CXCR 1,2
which integrin is important for gut homing by binding to MAdCAM?
α4β7
which complement is the most potent mediator of basophil and cutaneous mast cell degranulation?
C5a
which complement receptor is implicated in paroxysmal nocturnal hemoglobinuria?
CD55 (DAF); CD59
which complement deficiency is X-linked?
Properdin
which receptor facilitates transport of IgA across the epithelium in the gut?
Poly-Ig-receptor
Type of rejection associated with preformed ABO antibodies, HLA antibodies, and complement
hyperacute rejection
type of rejection involving non-complement fixing antibodies resulting in hemorrhage
Accelerated rejection
type of rejection T-cell and antibody mediated
Acute rejection
type of rejection leading to fibrosis and delayed type hypersensitivity in vessel walls, mediated by antibodies
Chronic rejection
