Immunology Flashcards
Direct pathway of allorecognition
Involves intact donor MHC presenting peptide to host T-cells
Indirect pathway of allorecognition
Refers to the presentation of donor MHC to host T-cells as processed peptides loaded onto host MHC molecules
AMR preferentially attacks which renal structures?
Peritubular and glomerular capillaries
Mixed lymphocyte culture measures?
differences in Class II proteins between cells
Engraftment with bone marrow stem cells takes how long?
median - 21 days
Engraftment with PBSC takes how long?
median - 14 days
Increases in number of mismatches in Host vs Graft direction increases risk of …
Graft failure
Phase I GVHD
Effects of conditioning regimen leads to tissue damage and generation of pro inflammatory cytokines (TNFa and IL-1).
Phase II GVHD
Donor T cells are activated by host APC. Activated T-cells produce cytokines (IL-2) leading to T-cell expansion
Phase III GVHD
Cytokine storm with positive feedback loop of cytokine production leads to activation of effector cells (CTLs and NK cells), which produce more pro-inflammatory cytokines (TNFa and IL-1)
Increases in the number of mismatches in Graft vs Host direction leads to …
GVHD
Structure of HLA Class I
alpha (heavy) protein chain, with 3 alpha domains, that is noncovalently associated with B-2 micro globulin (light) non-polymorphic protein
Structure of HLA Class II
2 distinct glycoprotein chains, alpha and beta
Recombinant HLA haplotypes occur when?
During meiotic cell division of germ cells (chromosomal replication –> X shaped chiasmata –> cross over site –> complementary exchange of genetic material)
T-cell mediated rejections preferentially attacks…
Tubules and arterial endothelium
Cord stem cell transplantation leads to less _____ due to relative immaturity of donor immune system at birth.
GVHD
Definition of epitope or antigenic determinant
minimum structural unit that can be recognized by a B or T-cell receptor
HLA gene is located on this chromosome
Chrom 6p
HLA gene is this many kbp long
4,100 kbp
HLA has this many loci
200
HLA is how many aa long
300
ACD stand for…
Acid Citrate Dextrose
Anticoagulant sample can be reclassified to remove_____ from plasma and yield _____
fibrinogen; serum
Anticoagulant of choice for Cellular Assays are ____ and should be stored at RT for no longer than____
Na Hep and ACD; 24 hrs
Anticoagulant of choice for Cytotoxicity assays are _____ and should be stored at RT for no longer than ______
Na Hep and ACD; 48 hrs
Anticoagulant of choice for DNA test is ______
EDTA and ACD
Cold storage makes it difficult to ________ for cellular assays
Isolate lymphocytes from other cells
Trauma respirator _______ PMNS, hence, lymphocytes
increases
Blood samples should be collected at lease _____ hours after last transfusion to avoid typing transfused cells
24
Centrifuge blood samples for …
10 mins at 850 - 1000 G (RCF)
Laboratory reports are to be achieved for this many years
2
Cytotoxic drugs ____ the number of lymphocytes and their viability.
decreases
EDTA stands for
ethylenediaminetetraacetic acid
EDTA, Sodium citrate, and sodium oxalate are not recommended for cytotoxicity assays because they act as chelaters that…
remove calcium and interfere with complement activation in CDC assays
For long term storage (>72 hrs) serum should be stored at least
70C
Fetal calf serum supplies a source of ______ for cells
protein
Cells in cellular medium should be should be stored at ___C
4
Lymphocyte count _____ with age
decreases
Lymphocytes have variability of HLA antigens, particularly
DR antigens
Clinical scenarios that lead to increased granulocytes, which can make it difficult to isolate lymphocytes
lymphadenopathy
viral, fungal, protozoan infections
HIV/AIDS
Immunosuppression
Lymph nodes are ____% T cells and ____ % B cells
75;25
OSHA stands for
Occupational Safety and Health Administration
Peripheral blood has ____% T cells and _____% B cells
50-90;5-20
Spleen has ____ %T cells and _____% B cells
50;50
Steroids _____ HLA antigen expression and _____ the number of granulocytes and platelets
decreases; increases
Serum can be stored at 4 - 8C for _____ hrs
<72
T cell stimuli for macrophage activation include ____ ligand and _____
CD40; IFN gamma
Activation of naive CD8 T-cells requires signal 1, which is ______, and signal 2, which is _______. Signal 2 is only present on ______.
Class I/peptide complex; costimulators/cytokines; professional APCs.
Process in which selection by antigen of B cells whose mutated receptors fit the antigen most tightly resulting in differentiation of only those B cells, which make antibodies of high affinity for their cognate antigen
affinity maturation
Complement activation pathway that is triggered by microbial surfaces and does not involve antibody
alternative pathway
Immunoglobulin heavy and light chains are held together by this
disulfide bonds
Best characterized T cell costimulatory pathway and has critical role in regulating T cell activation and tolerance
B7:CD28
Phagocytes and dendritic cells respond to signals via
Toll-like receptors
APCs bring antigen from tissue to ______ and from blood to _______.
lymph node; spleen
communication between T-cells and phagocytes is mediated by cytokines and ___:___ ligand interactions
CD40; CD40
chemoattractant cytokine - a small secreted protein which activates G-protein coupled to serpentine receptors
chemokine
Complement activation path way that is triggered by antigen-antibody complexes
classical pathway
Coreceptor for Helper T cells, cytotoxic T cells, and B cells
CD4, CD8, CD21/CD2
CD8 T cells kill cells infected with ______ pathogens
intracellular
Ig that mediate complement fixation
IgM, IgG1, IgG3
Ig that mediate opsonization
IgG1 and IgG3
Ig that mediate placental transfer
IgG2 and IgG4
Ig involved in mucosal immunity
IgA1, IgA2, IgM
Ig that mediates immediate type hypersensitivity
IgE
The ____ ligand on activated T cells delivers growth signal to B cells via ____ ligand on B cells; these along with T cell derived cytokine signals are delivered in germinal centers and contribute to clonal expansion and beginning of isotope switching and somatic mutation
CD40;CD40
Heavy chain constant regions are mad up of _____ domains
3 or 4
_____ Immune cells reconstitute before _____ immune cells. _______ are there first cells to reconstitute
Innate; adaptive; monocytes
Macrophages help stimulate acute inflammation through section of cytokines, mainly _____ and _____
TNF; IL-1
IgM tends to bing with _____ affinity to antigen than other isotopes, but its pentameric structure ______ avidity (ability to bind antigen)
lower; increases
Activated mast cells release histamine as well as ____
TNFa
T cell clonal expansion driven by IL-_ and IL-_ receptor
IL-2; IL-2
Th1 CD4 T cell differentiation stimulated by ____ produced by microbe-activated phagocytes. Th1 cell produce _____ and are effector cells that activate _____
IL-12; IFN gamma; macrophages
Th2 CD4 T cell differentiation stimulated by _____. Th2 cells produce ____ and ____, which promoted IgE and eosinophil-mediated anti-helminthic responses. Th2 may also down regulate ____ response
IL-4; IL-4; IL-5; Th1
Innate recognition components
PAMPs (Pathogen-associated molecular patterns)
Complement activation path way induced by MBL bound to target mannans
Lectin pathway
Lymph node:
T cells and dendritic cells reside in the ______
B cells reside in the _______
Plasma cells reside in the ______
para-cortex
cortex
medulla
_____ is a C1q like protein that can opsonize certain carbohydrate antigens and fix complement and thus helps to initiate signaling for innate immunity.
Mannose binding lectin
CD8 T-cell Fas: Fas ligand interaction cand lead to ______ of target cell
apoptosis
Granzymes from CD8 T-cells can activate intracellular ______, which can lead to apoptosis
caspases
Class I HLA generally bind and present _____ derived peptides to _____ T cells
intracellularly; CD8
Class II HLA generally bind and present ____ derived peptides to _____ T cells
extracellularly; CD4
Most potent APC
Dendritic cells
Naive lymphocytes remain in secondary lymphoid organs (______ and _______) where they search for cognate antigen. They do not track to _______.
spleen/lymph nodes/tissues
NK cells can promote inflammation by secretion of ____
IFN gamma
Natural killer complex is on chromosome ___
19
HLA-E presents peptide derived from _____
HLA-A,-B,-C
Number of lymphocytes in humans
100 Billion
Positive chemotaxis chemokines
IL-8 and INF
Primary lymphoid organs
Bone marrow and thymus
Protein degradation occurs mainly in ____ and ______
lysosomes and proteosomes
Pattern Recognition Receptors are present on _____ and bind to ______
APCs/PAMPs
Th2 cells ______ Th1 mediated functions by secretion of ___,___,___ which inhibit macrophage activation
suppress/IL-4/IL-10/IL-13
Th2 cells promote inflammatory actions by secretion of ____ and ____, that are dominated by eosinophils and mast cell for protection against helminths
IL-4/IL-5
IL-4 stimulates production of ____ antibodies, which opsonize helminths and bind to ____ cells
IgE/mast
IL-5 activates _____, which bind to IgE coated helminth by ___ receptors.
eosinophils/Fc
MBL binds ______ forming a complex that start the lectin complement pathway by cleaving C3 and C4
MASPs (MBL associated proteases)
Spleen:
T-cells located around _______
B-cells located in _______
Marginal zone, around the PALS, contains the ______
PALS
Primary and secondary lymphoid follicles
APCs
T cell activation requires 2 signals:
- MHC-peptide complex
2. Costimulatory signal, such as B7 (w/o this signal T cell will become anergic)
T-cell dependent pathways of B-cell activation requires secondary signal by _____ expressed on surface of activated ____ T cells.
CD40/CD4
T-cell dependent B-cell activation leads to B-cells that produce _____ affinity antibodies
High
T-cell independent B-cell activation does not trigger isotope switching or affinity maturation; thus, antibodies tend to be of _____ class with ____ affinity
IgM/low
T-cell independent pathways of B-cell activation requires secondary signal by _____ which respond to ______
Toll like receptors/PAMPs
TCR are composed of ____ and ____ chains
alpha and beta
Class I groove is approx ____ A long and closed at both ends, thus only accommodates _____ peptides
25/short
Portion of class I molecule that interacts with CD8 molecule on cytotoxic T cell
alpha 3 domain
Class II group is open-ended and thus can accommodate _____ peptides.
larger
Class II pathway is designed to present peptide derived from _____ proteins
extracellular
Portion of heavy chain associated with the light chain
VH domain and CH1 domain
Portion of the heavy and light chains that are involved in antigen recognition are the _______ ends and are referred to as ______ domains
N-terminal/Variable
Size of alpha heavy chain of Class I
40-50 kDa
Size of B2-microglobulin
12 kDa
Variable domains of TCR alpha and beta chains contribute to …
antigen binding site
Greg cells involved in immunological tolerance and characterized by cell surface expression of ____,____,____
CD4, CD25, FoxP3
Fluorescent dye that intercalates between the bases of DNA and RNA
Ethidium bromide
Excluding HLA antibodies, a positive AHG T cell crossmatch can be due to ______
macrophage contamination
Positive B cell XM does not usually cause hyperacute rejection because
vascular endothelium expresses little class II antigens
A ration between ______ for a cuvette spectophotometer indicates that the DNA sample is pure
1.8 - 2.0
A typical thermal cycler program fro HLA typing generally has how many cycles?
30
Absorbance 260nm/280nm values <1.8 indicate presence of ______
protein and membrane fractions
Absorbance 260nm/280nm values >2.0 indicate presence of ______
RNA contamination
Mechanism of action of Prograft (tacrolimus)
calcineurin inhibitor –> dephosphorylates NFKb —> prevents T-cell transcription
Mechanism of action of cyclosporine A
calcineurin inhibitor –> dephosphorylates NFKb —> prevents T-cell transcription
Mechanism of action of Cellcept (mycophenolate)
relatively selective inhibition of DNA replication in T cells and B cells by inhibiting de novo synthesis of purines
Mechanism of action of Imuran (azathioprine)
elatively selective inhibition of DNA replication in T cells and B cells by inhibiting de novo synthesis of purines
Mechanism of action of OKT3
monoclonal antibody targeted at the CD3 receptor
Positive control serum must be heat-inactivated to …
destroy any inherent complement activity
ASHI minimum labeling requirements
Identifier and date of collection
B5 splits
B51, B52
B12 splits
B44, B45
B14 splits
B64, B65
B15 splits
B62, B63, B75, B76, B77
B16 splits
B38, B39
B17 splits
B57, B58
B21 splits
B49, B50
B22 splits
B54, B55, B56
B40 splits
B60, B61
B70 splits
B71, B72
Best characterized T cell costimulatory pathway
B7:CD28/CTLA-4
B2 microglobulin encoded on chromosome _____
15
physiologic pH
7.2 - 7.6
Bw4 antigens
B51, B52, B44, B13, B27, B63, B77 ,B38, B57, B58, B49, B47, B37, B53, B59
BW6 antigens
B7, B8, B64, B65, B75, B76, B39, B18, B50, B54, B55, B56, B35, B60, B61, B41, B42, B45, B48, B67, B71, B72, B73, B7801, B8101
communication between lymphocytes and phagocytes to induce phagocyte effect functions is medicated by cytokines and ______
CD40 ligand: CD4 interactions
Hemacytometer cell count calculation
cells/ml = average count per large square (of which there are 9 large squares, each with surface area of 1mm^2) x dilution factor x 10^4
Channel shift in flow cytometry XM is determined by examining which histogram (axes)
FITC vs cell number
Chi-square test is used to…
assess significance o concordant and discordant reactions
The corrector for B cells
CD21/CD2
PCR inhibitors (4)
hemoglobin, heparin, ethanol, bleach
Temperature at which DNA denatures into single strands
94 - 96C
Temperature at which annealing of primers occurs
45 - 65C
Temperature at which replication/extension of amplicon occurs
72C
DNA sequences are always written from ____ to ____
5’/3’
EDTA inhibits PCR by…
inhibiting Taq via sequestration of MgCl2
Excessive dNTP concentration can lead to ______ and/or ______
mistakes in extension (incorporating the wrong base)/inhibition of Taq
Triton X-100 (detergent) lyses _____ in order to release _____
cell membrane/nuclei
Tween-20 (detergent) lyses _____
nuclei
Proteinase K destroys _______ bound to DNA. Proteinase K is destroyed by _______ which is important as it can degrade DNA polymerase
proteins/high temp (90C)
Frozen lymphocyte trays expire within _______
6 months
HLA DM is involved in _______
Loading antigen onto HLA-DR molecules
How can granulocytes in cell preparations interfere with crossmatch assay?
They can take up staining dyes resulting in false positive reactions.
Molarity =
moles of solute/liters of diluent
NaOH will do what do DNA?
denature
CD4 T cell generation of ______ helps drive class switching to IgE
IL-4
CD4 T cell generation of ______ helps drive class switching to IgA
TGF-beta
Besides frost bite liquid Nitrogen presents what other major danger to personnel
suffocation
Viability of negative control well in serological typing should be _____ %.
> 80
Polyacrylamide gels are used to separate fragments of DNA of _____ -______ base pairs
5 - 500 (small fragments)
Coding/sense primer
5’
non-coding/non-sense primer
3’
Primer length
20 - 30 bps
Water is categorized by type based on ______
resistivity
Endonucleases are
restriction enzymes
Purine bases
A and G
Pyrimidine bases
C and T
______ temp and ______ salt concentration favors higher stringency
High/low
Cytokine that plays critical role in the up-regulation of HLA-DR molecules
IFN-gamma
Degeneracy of the genetic code refers to ….
The redundancy exhibited as the multiplicity of three-base pair codon combinations that specify an amino acid.
Size of probe that would be expected to have a single target the haploid genome
16bp
The ______ prevents internal self-peptides from binding to HLA class II during HLA biosynthesis
invariant chain
______ divalent cations in ______ are essential in catalysis of _______. However, to much of it can ______ amplification
Mg/MgCl2/Taq polymerase/inhibit
Calculation for melting temperature (Tm) for short piece of DNA
Tm= (4 X GC pairs) + (2 x AT pairs)
Interaction btwn antibody and antigen is mediated by _______, _______, _______, and _______ (types of interactions/bonds)
hydrogen bonds/hydrophobic interactions, electrostatic interactions, Van der Waals interactions
Portion of heavy chain that is associated with light chain are the _______
N-terminal end (Variable domains)
Primary humoral immune response usually occurs within _______ days of stimulation
5 - 10
As the speed of centrifuged is doubled, the RCF is ________
quadrupled
0.9% normal saline is _____ g or NaCl in ______ ml of water
9g/1000ml
Greg cells are characterized by these surface markers (3)
CD4, CD25, FoxP3
Tris-EDTA buffer, pH 8.0 is good for long-term DNA storage at 40C, as the high pH ______ and the EDTA _____
inhibits acid hydrolysis/ inhibits nucleases
Bw4 antigens that are known to cross react with Bw6 sera
B27 B37 B44 B49 B51 B52 B53 B57 B58
Macrophages can be separated via uptake of _____ _____
iron fillings
CD25 AKA
IL-2 receptor
Mechanism of action of Sirolimus, aka rapamycin
Mtor inhibitor
Chemokines are ligands for ______ coupled receptors
G-protein
Cytokines are ligands for ______ coupled receptors
JAK-STAT
M1 macrophages are more _______ and promote _____ responses
proinflammatory/Th1
M2a macrophages are stimulated by _______ and involved in resistance to _______ infections
IL-4/parasitic
M2b/c are more ________ and release ______ and ______
anti-inflmmatory/IL-10/TGF-B
vital dyes stain ______ cells (examples include _____)
injured;dead/ethidium bromide, eosin-Y
supravital dyes stain ______ cells (examples included _____)
viable;alive/acridine orange and CFDA
NKG2A and NKG2B are _____ and have associated ______ sequences
inhibitory/ITIM
NKG2C, NKG2E, and NKG2H are ______ and associate with the ______ accessory molecule
DAP12
NKG2 molecules are generally associated with ______ surface receptor, except ______ which forms a homodimer and is usually associated with _______ accessory molecule; it is a potent activator that can overcome inhibitory signals from the same target cell
CD94 (short cytoplasmic tail)/NKG2D/DAP10
Frame work KIR genes (4)
3DL3
3DP1
2DL4
3DL2
KIR2D receptors have ____ extracellular domains and bind _____ ligands.
2/HLA-C (residues 77 & 80)
KIR3D receptors have ____ extracellular domains and bind _____ ligands
3/HLA-Bw4 (residues 77-83)
Group 2 HLA-C alleles, including _____ (4), are ligands for KIR _____
C2, C4, C5, C6
KIR2DL1
Group 1 HLA-C alleles, including _____ (4), are ligands for KIR____ and KIR____
C1, C3, C7, C8
KIR2DL2 and KIR2DL3
HLA Class II Synthesis - has ______ chain in ER for stabilization. This chain is cleaved in the acidified endosome and the _____ molecule remains to stabilize the molecule until peptide is loaded
invariant/CLIP
Class I peptides are ______ (~____ - ______ aa long)
short/8-10
Class II peptides are ______ (~____ - ______ aa long)
long/up to 30
Positive selection occurs in the _____ of the thymus
cortex
Negative selection occurs in the _____ of the thymus
medulla
B2 microglobulin encoded on this chromosome
15
HLA-DO and -DM help to regulate this function
peptide insertion
DR2 splits
DR15 and DR16
DR3 splits
DR17 and DR18
DR5 splits
DR11 and DR12
DR6 splits
DR13 and DR14
celiac disease HLA association
DQB102:01 with DQA105:01 (DQ2.5)
Type I DM HLA association
DQB102:01 and DQB03:02
narcolepsy HLA association
DQB1*06:02
______ binds to MHC Class II and releases _____ fragment to allow peptide to bind
HLA-DM/CLIP
_____ inhibits HLA-DM to expand the repertoire of peptides presented by Class II molecules. It allows for ____ peptides to be presented
HLA-DO/self
Class I heavy chain is stabilized by ______ until B2 micro globulin binds
calnexin
Peptide is delivered by _____
TAP
Peptide-loading complex consists of ______ (5)
TAP, tapasin, PDI, ERp57, calreticulin
Bw4 sequence
TLLR/IALR
Aw4 sequence
IALR
Bw6 sequence
NLRG
These three Bw6 alleles have 76V instead of 76Q aa sequence difference
B*46:01, 73:01, 18:06
KIR encoded on this chromosome
19
HLA-E presents _____
self peptide derived from leader sequences of HLA-A, B, C
HLA-F can exist without stabilization from ______ for a while and guide itself to the surface to pull in exogenous protein. This protein can then be loaded onto Class I or II. HLA-F can also donate its ______ to stabilize Class I
B2 microglobulin/B2 microglobulin
HLA-G is expressed on _______ and provides protection during pregnancy from NK cells as placenta does not express Class Ia. HLA-G also binds KIR_____ within the _____ to inhibit the _____ cell.
fetal trophoblasts/2DL4/endosome/NK
MICA and MIC B do not have ______ or ______ like Class Ia molecules. They can act as a ligands for ______, which activates NK cells
peptide/B2 microglobulin/NKG2D
CD1 present the ______ portion of ______ to T-cells
hydrophillic/lipids
Human hemochromatosis HLA association
A*03:01
ERp57/PDI responsible for binding of ______ to ______
tapasin/TAP
______ removes ______ terminus of protein to yield peptide of 8-10 aa for Class I molecular groove
ERAP/N
Piptide - HLA interactions is primarily through _____
H-bonds
INF __, ___, ____ can induce Class I expression, but only IFN ____ can induce Class II
alpha, beta, gamma/gamma
_____ is the transcription activator for Class I
NLRC5
_____ is the transcription activator for Class II
CIITA
HLA association with carbamazepine and phenytoin hypersensitivity
B*15:02
HLA association with allopurinol hypersensitivity
B*58:01
HLA association with abacavir and flucloxacillin hypersensitivity
B*57:01
