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)
