Hematology and Immune Physiology - Theoretical Questions Flashcards
Hematopoiesis:
How much RBCs and WBCs are forming relatively out of 10^11 daily ? Why?
75% - WBC (Shorter life span)
25% - RBC (120, Longer life span)
Hematopoiesis: where? In fetus and Adult
Forms of production site?
Fetus - Liver
Adult - Bone marrow:
Yellow Bone marrow - Inactive (fatty)
Red Bone Marrow - Active or Hyperplastic (HSC, HC and Stromal cells)
Hematopoietic stem cells:
Markers, potency, function
c-Kit and CD34
Omnipotent to Oligopotent to Multipotent
Self renewing asymmetrical divisions
What is special about Multipotent progenitor cells (MPP) ?
The first cell formed in hematopoiesis unable of self renewal. From it the formation pathway divides to Myeloid and Lymphoid Lineages
What are the synonyms for the the Progenitor cells and Hematopoietic growth factors?
Progenitor cells - colony forming units (CFU)
Hematopoietic growth factors - Colony stimulating Factors (CSF)
What are CLPs? what are their outcomes?
CLP -Common lymphocyte precursors: Lymphoid lineage - Forming T and B-Cells (naive) and NK cells
What are CMPs? what are their outcomes?
CLP -Common Myeloid precursors: Myeloid lineage - Forming Monocytes, Mast cells and Megakaryocytes and Erythrocytes
What determines the life span of the blood elements?
RBCs - Rigidity of old cells cause clearing in hepatic circulation.
Platelets - Used up continuously by micro injuries
WBC - Used up continuously by Immune functions
What causes the Stress Hematopoiesis?
Hypoxia - HIF1-Alpha - EPO - Erythrocytes↑
Infection - Granulocytes↑
What Cytokines? Examples for Hematopoietic CSF?
Glycoproteins that cause transcription through TyrK mechanism. IL3 is a CSF for Myeloid Line.
EPO- Erythrocytes↑
What is the general principle for the Hematopoiesis regulation?
Early stage - Many factors (Overlapping)
Late stage - Fewer specific factors
What is an Hematopoietic Niche ?
Cell to cell interaction in the bone marrow for differentiation signaling - Causes the Divisional Asymmetry . Chemokines - Regulate the movement of Stem cells through these.
How are Thrombocytes formed?
Budding off the the Megakaryocytes into the vessels lumen. Cell Fragments.
What are the Reticulocytes?
Final RBCs progenitor still containing RNA for Hemoglobin synthesis (After nucleus removed)
Why are the kidney responsible for the EPO secretion ? (Mostly, Some is from liver)
They have the smallest AVDO2, Meaning their JG cells can sense with the greatest resolution the changes in O2 supply.
what ae the derivatives of the Monocytes developing course ?
Osteoclasts, Dendritic Cells, Macrophages, Kupffer cells and Alveolar Macrophages.
What regulates the Formation of Platelets?
Thrombopoietin from Liver.
What is necessary for Erythropoetin?
What could happen in shortage of each?
Folic Acid, B12 and Iron.
Iron↓ - Microlytic Anemia
Folic Acid and B12↓ -Megaloblastic Anemia
What are the steps of Primary hemostasis?
1) Vasoconstriction
2) Platelet adhesion
3) Platelet Activation and Aggregation
What are the steps of Secondary Hemostasis?
Activation of Coagulation factors and Fibrin
What are the steps of Fibrinolysis?
Activation of Fibrinolysis and Lysis of Plug
What causes Vasoconstriction in Injury?
Endothelin released from raptured Endothelial cells and Neurogenic Intermediates also released: TH5, K, THX2
What causes Platelets Adhesion?
vWF binding them to Collagen of Subendothelial tissue.. With GP4 and GP2b binding proteins.
What causes Activation of Platelets (6)?
Collagen - Subendothelial Tissue (Gq) TXA2 - from other platelets 5HT - from other platelets Adrenaline - Blood and from other platelets Thrombin - Formed in clotting PAF - from WBCs
What happens to activated platelets?
They form lamellipodia for interactions with other platelets and They release ADP and THX2 to cause other platelets to adhere. They also have a negative phosphatidylserine surface allowing for Coagulation factors activation.
What prevents Platelets aggregation?
NO and PGI2 coming from Uninjured Endotheliales
What is the role of Vitamin K in Hemostasis?
Gla proteins formation: Vit K in its reduced form is a cofactor for Carboxylases in the liver that react to form the Gamma-Carboxyglutamic acids residues (Gla) essential for binding to phosphatidylserine surface of Platelets and Coagulation.
Extrinsic Pathway of Coagulation:
Factor VII forms a complex with Ca and Tissue factor (F3) which is then able to cleave and Activate Factor X.
Intrinsic Pathway of Coagulation:
Factor XII is conformationally changed and activated by Activated Platelets which Cleaves Factor XI which with Ca Cleaves Factor IX which forms a complex with factor VIII and Ca to Cleave Factor X.
Common Pathway of Coagulation:
Factor X activated by Intrinsic or Extrinsic Pathway Cleavage. With Factor V and Ca forms Prothrombinase complex which is able to Cleave thousands of Prothrombins and form Active Thrombins (Amplification)
Which factors are cleaved by Thrombin?
Fibrinogen (Factor I), Factors V, VIII, XI, XIII
What is the job of Factor XIII?
Transglutaminase that crosslinks together fibrin mesh to further strengthen the structure (Ca cofactor)
What happens to Factor VIII if they are not active?
1) Get degraded
2) Bound to vWF in blood
What is the way Thrombin inhibits Coagulation?
Thrombomodulin causes changes in specificity for Thrombin that inactivate Factors V and VIII.
This happening in a complex with APC and Protein S as well.
What is the way Antithrombin inhibits Coagulation?
Potentiated intrinsically by Heparan Sulfate and Extrinsically by Heparin it directly inactivates thrombin.
What is the way TFPI inhibits Coagulation?
Activated by Xa it inhibits FVII-TF Complex
What are the Vit K dependent Coagulation factors?
What inhibits their formation?
Factors II, VII, IX, X and Protein C, because all of them have a Gla domain. Warferin and Coumadin blocks VitK reductase and lead to Gla Domain to not form.
What is the in vitro way to stop coagulation?
EDTA and other Ca Chaleators. These prevent the High Ca level needed for the Cascade to occur.
What are the roles of Platelets after Primary Hemostasis?
Clot retraction and Plasminogen-Activator Inhibiting Factor. As well as secretion of VEGF and PDGF which help Growth of Endothelial and SMCs around clot.
What is the job of tPA? What does it bind while it does it? Other factor is able to replace it?
tPA activates Plasminogen, Fibrin dependent.
Urokinase Plasmin Activating factor (uPA).
Both come from Endothelial Cells
What are the inhibitors of the Fibrinolytic pathway?
PAI-1 - Inactivates uPA and tPA
Alpha-2-Plasmin Inhibitor - Inactivates Plasmin
TAFI - a Carboxypeptidase inhibiting Plasmin action by changing Lysine residues on Fibrin.
What are the Patterns on Molecules signaling for Macrophages to eat them (Opsonization)?
PAMPs - Pathogen Associated Molecular Pattern:
Mannan, LPS, Peptidoglycan also Viral DNA or RNA
What helps Macrophages to recognize PAMPs?
PRR -pattern recognition receptors
Can cause Phagocytosis in Macrophages and Neutrophills or Signaling molecules release if Pathogen number is High.
What are the Most iMportant Signaling PRR? Subtypes?
Toll-Like Receptors:
Extracellular - types 1,2,4,5,6
Intracellular- 3,7,8,9
Once TLRs are activates what gets secreted? Targets?
They cause activation of NF-kB that allow transcription of TNF-Alpha, IL-1, IL6 which causes inflammation
What are the 5 Signs for Inflammation?
1) Fever
2) Swelling
3) Pain
4) Redness
5) Joint Immobility
What are the Leukocyte Migration steps? Protein factors?
Rollin - Selectins
Adhesion - ICAMs
Diapedesis -Integrins (Between the Endothelial cells)
Migration - Chemokine (GPCR) dependent in the CT
What is the Complement System?
A system of Circulating proteins that are integrating the Innate Immune response like Opsonization, Chemotaxis and Lysis of Bacteria. Activated by the Pathogen.
What are the Pathway initiations of the Complement system?
Classical: Pathogen-Antibody Fc portion is bound by C1 protein
Lectin: Mannose is Bound by Lectin which binds C4
Alternative:C3b binds directly to the Pathogen
What are the Complement system proteins? by order
C1 - C4 - C3b - C5b - C6…9
What is the purpose of C3a and C5a?
They get activated by Mast cells and act as a chemotactic agents for Inflammation and Attracts Phagocytes
What could form from C5b to C9?
MAC - Membrane attack complex:
Causes Bacteria Lysis
What is the Purpose of C3b? How is this process happening without it?
It is an Opsonin - Attracts Phagocytosis by Macrophages.
Otherwise could occur by Macrophage Binding the Antibody for detection or PRR
What is CRP?
C- Reactive Protein
Allows for Opsonization of Microbes and Complement system activation
Eosinophils - Activity?
Major Basic Proteins produce ROS for Oxidative attack.
Efficient against Multicellular Parasites.
Basophils - Activity?
- IL6, TNF-Alpha, Histamine and Heparin Production
- Inflammatory Response and Allergies
- Efficient against Multicellular Parasites.
Neutrophil - Activity?
- Phagocytosis in Bacterial Infections
- Most efficient in Phagocytosis and Oxidative Burst
Dendritic Cells? - Activity?
- Capable of Phagocytosis
- “Professional” Antigen Presenting Cells for Helper T cells (Link Between Adaptive and Innate)
Natural Killer cells - Activity?
They descend from similar lineage as T cells.
Kill MHC-I Negative cells. Secrete Granzymes, Perforins and Inflammatory Cytokines.
What do we measure in PT?
Extrinsic Pathway
What do we measure in PPT?
Intrinsic pathway
What does the Amount of Fibrinopeptide A tells us?
Amount of Fibrin Formed
What does the Amount of D-Dimers Tells us?
Efficiency of Thrombin, FXIII and Plasmin
What is the function of B-Cells as part of the adaptive Immune system?
Immunological Memory
Stronger and more specific response
What are the Primary Lymphoid organs?
Bone marrow and Thymus
This is where the B and T cells mature (RESPECTIVELY)
What are the Secondary lymphoid organs?
Spleen, Lymph Nodes and MALT
These are sites of Initiation of Adaptive Immune response
Where are B-cells found in the Lymph Nodes?
Primary lymphoid follicles
Lymphocyte Patrol : This is where they receive the Antigens and activate, and after the response is done washed back to blood
What are the special features of the Immune response ?
1) Specificity - Epitope recognition
2) Diversity - VDJ recombination allows for different Antibodies
3) Memory - Each exposure generate more specific Memory cells
4) Clonal Expansion - allows for amplification of Plasma or Memory cells
Antibodies different positions:
Antibodies are Immunoglobulins that could be membrane bound as antigen receptors of B cells or Secreted by Plasma cells to Mucus, Interstitial cells and plasma
What are the different parts of the antibody:
What 4 type of domains are present? what is their purpose?
- 2 Identical Light chains and 2 identical Heavy chains
- These are held together by S-S Bridges
- Variable domains for recognition: V-Heavy and V-Light
- Constant domains for mediation: C-Heavy and C-Light
What is left of the Antibody once cleaved by papain? what are they originally composed of?
- 2 x Fab (Antigen binding): C1 and V Heavy
- 1 x Fc (Crystallizable) : C2 and C3 Heavy
What gives us the 5 x 10^13 total receptor diversity?
VDJ Recombination: 50V, 25D and 6J genes
Junctional diversity: Addition/Removal of Nucleotides
Properties of IgG:
- Monomer
- Mediate Opsonization
- Mediate Complement sys
- can neutralize bacterial toxins
- CROSSES THE PLACENTAL MEMBRANE
Properties of IgA:
- Dimer
- Mucosal Immunity
Properties of IgM:
- Pentamer
- Used as BCR (Immature and Part of Mature)
- Mediate Complement sys
Properties of IgE:
- Monomer
- Part of Allergic Reaction
- defence against Parasites
Properties of IgD:
- Monomer
- Part of BCR (mature)
What are the positive and negative selections in B cells development?
- Positive: Chains Function test, if not - Apoptosis
- Negative: if Recognize self antigen - Apoptosis
What does the BCR have other than IgD and IgM?
What is its importance?
IgAlpha and IgBeta that form Immunoreceptor tyrosine based activation motif) ITAM. Phosphorylated upon antigen recognition - NF-kB - Proliferation and differentiation
What can activate B-Cells?
Free Antigens or Antigen presenting cells
T-Cells dependent activation of B-Cells:
T dependent Antigens (More harmful in AIDS) taken and presented by T cells MHC-II molecule. BCR + Antigen Epitope + MHC-II make a sandwich and T cells now secrete IL4 that allow B-cell differentiation and growth.
Isotype Switching:
A process that may occur for B-Cells as they activate.
They start producing and Secreting IgGs instead of IgM for a greater overall effect.
T-Cells Independent activation of B-Cells:
TI antigens (T Independent) are recognized by BCR. Rapid activation but less Isotype switching in comparison with T-dependent (more IgM) so less effective.
Plasma cells Jobs: what is the result?
Secreting Antibodies, Clonal expansion and becoming Memory cells. This is why after the second exposure to the Antigen activated Memory cells are able to produce a much broader stronger Response.(Acquired Immunity)
What are the types of T-cells? What are their Markers?
What are the MHCs that they recognize? What are their jobs?
T Helper Cell - CD4+ - MHC-II - Activation of B cells
Cytotoxic T Cell - CD8+ - MHC-I -Destroy Tumor/Virus cells
What is the Positive selections in T cells development?
At first Immature T-cells are both CD8 and CD4 Positive.
The T-Cell gets to differentiate if there is a binding of Either one of the MHC-I or MHC-II cells of the Thymoepithelial cells (Accordingly). Loose Bind= Apoptosis (FAS ligand).
What is the Negative selections in T cells development?
After Positive selection, in the Medulla, Dendritic cells expose the T cell to own Antigen. Binds too tight = Apoptosis / Binds loose = differentiation. Prevention of Autoreactive cells.
T -Cell receptors:
- 1 Antigen binding site (Antibodies have 2)
- Always bound
- Beta+Alpha+Zeta chains (Variable +Constant)
- ITAM for NF-kB activation
What is MHC?
Major Histocompatibility Complex. Mediates recognition in the Immune response.
MHC-I: All nucleated cells (non on RBC)
MHC-II: Only on Antigen presenting cells: Dendritic, Macrophage and B cells
Explain the function of Cytotoxic T-Cells after activation:
Infected virus/tumor cell forms a complex with -
MHC-I+Epitope+TCR
Release of Granzymes and Perforins.
Perforins - make a pore in the infected cell
Granzymes - come in the cell and activate Caspases and Apoptotic cascades.
What are T-helper cells -1 doing?
Activating Macrophages (Another adaptive to innate link). Can recognize Antigen presenting cells MHC-II
What are T-helper cells -2 doing?
Activating B-cells. CD4+ Most Important job.
Can recognize Antigen presenting cells MHC-II
Peripheral Tolerance of T cells:
Regulatory T cells can inhibit reaction against own T cells by specific cytokines. (CD25+)
Give examples for Autoimmune diseases: name the targets or consequences
Myasthenia Gravis - Nicotinic Ach receptors
Multiple sclerosis: Myelin Sheath Toughness
Graves: Goiter
Peripheral Tolerance of B :
Anergic B-Cells that are unresponsive or even silence other responses of other Bs to the Epitope.
What are common for the Innate and Adaptive Immune?
Fc of Antibodies
Complement system
NK cells
What does Interferon do?
Inhibits replication in surrounding cells of Infected Viral cell.
What is Cytokine Switch?
T helper cells type 1 Inhibit T helper Type 2 (Cross inhibition)
What is the basis of the blood groups in Human?
The Presence or Absence of Carbohydrates on RBCs.
There above 30 antigens on RBCs but most are not reactive. Specific transferases carry them to surface.
What is the H antigen?
Fucose (Fuc)
What is the A antigen?
N-acetylgalactosamine (NaC) (On top of Fucose)
What is the B antigen?
Galactose (Gal) (On top of Fucose)
What is the O Antigen?
No additional Enzyme transferase activity. Meaning there is only the Fucose antigen (H)
What is the dominance of the transferase enzymes that leads to the antigens of blood groups?
A, B allele - Codominant
O allele - Recessive
What will cause an agglutination reaction with Blood Type A?
Since it has Anti-B (Antibodies) it will have agglutination with blood transfusion from B and AB blood types.
What will cause an agglutination reaction with Blood Type B?
Since it has Anti-A (Antibodies) it will have agglutination with blood transfusion from A and AB blood types.
What will cause an agglutination reaction with Blood Type AB?
Since it has no antibodies for other blood groups it will have NO agglutination with blood transfusion from ANY type.
What will cause an agglutination reaction with Blood Type O?
Since it has Anti-A and Anti-B (Antibodies) it will have agglutination with blood transfusion from A, B and AB blood types. Allows Transfusion only from O type.
What are the ABO Antibodies in the Immune system made of? Why is this important in Pregnancy?
IgM. Because these are Pentamers they do not cross the Placental barrier.
What happens when there is incompatible blood type transfusion? What Immunological events?
Antibodies bind the foreign RBCs Antigen. Activation of Complement system and Phagocytosis - Ultimately Intravascular Hemolysis.
What is the treatment when incompatible blood type transfusion has occurred?
Antihistamine, Corticosteroids and Epinephrine.
Other question on why
What is the basis of the Rhesus system?
1 D (Dominant) Antigen (Out of 6 types that are weak). Antigen D is a protein channel not understood. Rh positive means there is D+ on the RBC surface.
What is the Genotype, Antigen and Antibody product of Rh positive?
Genotype: DD and Dd
Antigen Product: D
Antibody: No Anti-D
What is the Genotype, Antigen and Antibody product of Rh negative?
Genotype: DD and dd
Antigen Product: d
Antibody Anti-D: EXPRESSED ONLY AFTER EXPOSURE
What are the D Antibodies in the Immune system made of? Why is this important in Pregnancy?
Anti-D is a IgG. Means that it can cross the placental barrier! after first pregnancy to a Rh+ child the mother can be exposed and IMMUNED (Anti-D production). The second child (If Rh+) RBCs could be attacked by Anti-D .
What could be done to prevent Rh incompatibility in pregnancy? 2 Ways :
1) C- Section: Prevents delivery from Mixing Maternal and Fetal blood.
2) Injecting Mother with an Inactive Anti-D before delivery neutralizing the fetal Antigens.(Pre-Emptive)
What is the Two sided test? What is being checked in each part?
Checking the Compatibility before Transfusion:
Forward: RBC of Patient + Antibodies (Anti-B, Anti-A)
Reverse: Serum Patient + A/B/O blood types cells
After seeing the results and understanding that both patient and donor are compatible, What is the next step?
Taking a sample from recipient and donor and check with donor in a sample tube. In reality there are patches like structures for fast checking in case of emergency.
Anaphylactic Reaction Defenition:
Immediate Hypersensitivity by chemical stored in mast cells - Histamine, Leukotrienes or Heparins.
Could occur upon Incompatible blood transfusion.
Anaphylactic Reaction 1st Exposure:
1st Exposure:
1) IgE by plasma cells are produced
2) IgE binds Mast cell membrane (or Basophil converted Mast cell)
Anaphylactic Reaction 2nd Exposure:
2nd Exposure:
1) Same Antigen binds IgE of Mast cells.
2) Mast cells release content: Histamine, Leukotrienes or Heparins (Also ECF-A)
Anaphylactic Reaction: what is the effect of the Histamine, Leukotrienes or Heparins (Also ECF-A) released from Mast cells?
Bronchoconstriction - Inability to breath
Vasodilation - Low blood pressure
Could be deadly.
Anaphylactic Reaction: Treatment?
Antihistamine, Corticosteroids and in severe cases Epinephrine
What is the distribution of the blood types?
A -40% B -20% AB - 10% O - 30% Also: Rh+ : 85% Rh- : 15%
