Tools needed for Host Defense Lecture Sep 30 Flashcards
What are all immune system cells descendants of?
A pleuripotent hematopoietic stem cell found int he bone marrow
What two signallers will regulate the repertoire of cells produced during hematopoiesis?
growth factors and cytokines
What are the two important subdivisions of hematopoiesis projenitors?
Common Lymphoid Progenitors and Common Myeloid Progenitors.
The myeloid cells include…
Neutrophils, Eosinophils, Basophils, Monocytes and Dendritic Cells. Monocytes transform into macrophage upon entry to tissues. Mast cells are assume to be populated into tissues by blood borne precursor cells produced in the Bone Marrow.
The lymphoid cells include…
B-cells, T-cells, NKT cells and NK cells
How do B cells and plasma cells (further differentiated B cells) differ in how they express immunoglobulin?
B cells express immunoglobulin as the antigen receptor and will secrete homologou immunoglobulins as antibody
Plasma cells do NOT express surface immunoglobulin but secrete large amounts of antibody
What are the granular white blood cells?
what are the non-granular white blood cells?
THe granular inclue the leukocytes (like mast cells and basophils) - they collect their cytokines in granules and undergo triggered release
The non-granular cells include monocytes and lymphocytes (they immediately release their cytokines, so there is no triggered release)
Where do blood cells develop?
All the stem cells are located in the bone marrow
the myelocytes and lymphocytes will develop in the bone marrow
the T cells will develop in the thymus (newborn through puberty only)
What do macrophages mainly use to destroy bacteria?
ROS
How do monocytes and macrophages differ?
the monocyte is in circulation
macrophages are in the tissue
otherwise they are the same thing
a macrophage is more irregularly shaped.
What is the main role of a mast cell?
Start inflammaton by releasing histamine, heparin, and TNF alpha
What three things will cuase mast cell degranulation?
antibodies coopted by the mast cell bind the antigen and cross link
injury
complement activation
What is the main role of a neutrophil?
They are the first respinders that phagocytose and activate bactericidal mechanisms. then they die.
How are neutrophils released into circulation?
THey are short lived and produced on demads…
a large number of cirulatory neutrophils are bound to the surface of bascular beds
stress with cortisol and epinephrine will stimulate demarginalization - release of neutrophils into circulation
What are the most prevelane leukocytes?
neutrophils
How do neutrophils recognize invaders?
They have receptors for antibody Fc regions and receptors for complement
What are eosinophils associated with?
Which antibodies mediate their action?
They are involved in attack on helminthic parasites and allergies
they have receptors for IgE
They secrete peroxidase and leukotrienes
Where are basophils located?
What do they release?
Basophils are located in the lymph nodes are are associated with histamine release in hypersensitivity responses. They sample the same materials the T cells are sampling in the lymph nodes and are activated by IgE
They are the samllest and least abundant
the main function is considered to be regulation of the inflammatory processes
What do NK cells screen for?
What will they induce?
Do they have an antigen receptor?
They screen for absence of MHC Class 1
if no MHC is presented, they will induce apoptosis in the target cell
they do NOT have an antigen receptor
WHat do dendritic cells do?
They will pick up material rom sites of inflammation using PAMP receptors.
They will then present the antigens on MHC Class II displays to the naive T cells to activate them
What are some characteristics of cytokines?
they are soluble mediates that are small glycoprptines synthesized on demand
they act through autocinre and paracrine methods only
THey are uiquitously found
THey direct cellular differentiation through sequential cascade patterns
WHat cytokines direct cell development?
growth factors initiate the whole thing, but the interleukins (IL3, 4, 5, 6, and 7) take over to refine the development process as needed
What MCH class is expressed on dendritic cells, macrophges and B cells?
MHC class 2
What cells express MCH class 1?
What’s presented on class 1?
all cells except for RBCs
The antigen display is all self proteins
What determines what kind of T cell a T0 cell will develop into?
the type of PAMP presented by the dendritic cell on its MCH class 2
