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chpt 2 2


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formation and development of red or white blood cells. begins in first weeks of development
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
-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?
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
growth factors that influence the development of blood cells during hematopoiesis.
hematopoeitic inducing microenvironment
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
roles of non-lymphocyte leukocytes:
engulf/destroy microorganisms
present antigens
secrete cytokines
3 populations of lymphocytes
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.
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
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
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:
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?
-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?

-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

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