chpt 2 2
Terms
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- hematopoiesis
- formation and development of red or white blood cells. begins in first weeks of development
- pluripotent
- able to differentiate in various ways to generous many different cells from one hematopoeitic stem cell in our case
- What does the multipotent HSC differentiate into?
-
-Lymphoid progenitor
or
-Myeloid progenitor - progenitor cells
- cells that have lost the capacity for self-renewal; committed to their cell line.
- What does the lymphoid lineage give rise to?
-
-Bcells
-Tcells
Natural Killer cells
some dendritic cells - What does the myeloid lineage give rise to?
-
-Progenitors of RBCs
-White blood cells including granulocytes, monocytes, mast and dendritic cells, and platelets. - stromal cells
- non-hematopoietic cells that support growth/differentiation of hemato cells
- cytokines
- growth factors that influence the development of blood cells during hematopoiesis.
-
hematopoeitic inducing microenvironment
HIM -
provided by the stromal cells that hematopoietic cells grow on.
-give factors that promote cell growth/differentiation... - 2 identified cytokines:
-
-CSF - colony-stimulating factors
-EPO - Erythropoietin - How receptors on blood cells is related to differentiation:
- Target cells must have the right receptor for a given cytokine (growth factor), this is a point of commitment of a progenitor cell to a line.
- Macrophages and Thelper cells as growth factors:
- during infection activated macrophages and T helpers produce growth factors that stimulate hematopoiesis.
- transcription factors that genetically regulate hematopoiesis
-
Gata-2 - regulates lymphoid, erythroid, and myeloid lineages.
Ikaros - regulates only lymphoid cells. - Inflammatory response - apoptosis or necrosis?
- NECROSIS; apoptosis does not induce an inflammatory response.
- central cells of immune system
- lymphocytes
- roles of non-lymphocyte leukocytes:
-
engulf/destroy microorganisms
present antigens
secrete cytokines - 3 populations of lymphocytes
-
Bcells
Tcells
NKs - natural killers - NK cells
-
Natural killer cells
large granular lymphocytes - Naive B or T lymphocytes
-
resting B/T lymphocytes that have not interacted with Antigen.
Stuck in the Go phase of cell cycle; small, under-developed;
Interaction with Antigen makes them go into cell cycle. - Lymphoblasts
- lymphocytes that have been exposed to antigen and progressed through cell cycle.
- Role of Lymphoblast
- proliferate, and differentiate into effector or memory cells
- Effector lymphocytes
-
various methods to eliminate antigen:
-Plasma cells: bcells that secrete Ab.
-Thelper cell: secretes cytokines
-Tcytotoxic c: kills infected cells. - Memory lymphocytes:
-
a population of cells that persist for LIFE!!
makes us immune to many pathogens.
-look like small lymphocytes, but are different. - Characteristics of Bcells
-
-Synthesize/display Ab (immunoglobulins)
-Class II MHC permits APC function - How Bcells work in a nutshell
- -Interaction of naieve Bcell with Ag or interaction with Thelper cells and macrophages causes activation and differentiation of multiplied Bcells into plasma or memory cells. Plasma cells die within a couple weeks, memory live forever.
-
B is for..
T is for.. -
B is for bone marrow
T is for Thymus - whats a specific way that the innate immune system interacts with adaptive?
- chemotactic factors released attract macrophages, which release cytokines that activate thelper cells; thelper cells activate b cells, which then produce antibody that can act as an opsonin and regulate macrophage (innate) activity
- two major groups of cells involved in an effective immune response:
- tcells and APC
- altered self-cells
- cells that display foreign antigen complexed with MHC1
- APCs:
-
Bcells
Macrophages
Dendritic cells - 4 types of immune dysfunction
-
-allergy (IgE binds antigens, degranulation)
-Graft rejection
-Autoimmunity - lost self/nonself sense
-immunodeficiency - a part is broken - 4 ways to regulate Hematopoiesis:
-
1. Cytokines - EPO, CSF
2. Stromal Cells
3. Cytokine receptors
4. Programmed cell death - What is the best type of cell to inject if you need to replenish bone marrow after disease? then what
-
1. Stem cells - only 1 is necess. in theory
2. Progenitor cells. (Differentiated cells can be antigenic and attacked) - What is the general ratio of blood cells?
-
RBC - highest; 5,000,000
Platelets; 2,500,000
Leukocytes; 7,300
Neuts
lymphs
monos
eos
basos - What is the first cell to arrive during acute infection, and the most abundant leukocyte?
- Neutrophil - phagocytosis w/ lytic enzymes in its granules to breakdown.
- What do eosinophils play a major role in eliminating?
- Parasites (tapeworms, worms in intestine and stomach)
- What are mononuclear cells?
- predecessors of macrophages - capable of phagocytosis.
- Special characteristic of macrophages:
- pseudopodia - foot used for phagocytosing foreign substances.
- 2 types of mononucleocytes, where they are:
-
Monocytes - in the blood for a couple days.
Macrophages - in the tissues - 3 functions of macrophages:
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1. Phagocytose particulate matter - Ag-AB complexes; this finishes work of Ab.
2. Ag presentation
3. Secretion of factors - What factors are secreted by Macroph?
-
1. Cytokines
2. Lysis factors
3. Complement
4. Defensin - What is defensin?
- a factor released by macrophages that drills holes in bacterial membranes and causes lysis.
- By what 2 pathways do Macrophages and Neutrophils their targets?
-
1. O2 dependent
2. O2 independent - What is O2 dependent killing?
- Macrophages undergo a Respiratory burst, generating reactive oxygen & nitrogen intermediates in lysosomes. They fuse with phagosomes, and break down engulfed material.
- What factors mediate O2-independent killing in macrophages?
-
-Defensins
-TNF-alpha
-Lysozyme
-Hydrolytic enzymes - What is the purpose of the granules in Basophils?
-
NOT to kill; rather,
Inflammatory Mediators -
What inflammatory mediator do basophils and mast cells contain?
What response are they effector cells for? -
-Histamine
-Allergic response (Type 1 hypersens.) -
What is the major role of Dendritic cells?
What allows them to do this? -
Antigen presentation.
Phagocytic ability (to take up Ag to present)
MHC class 1 and 2