Hematopoiesis Flashcards
Where do cells of different lineage and function develop from?
The pluripotent stem cell
True or False. Hematopoiesis declines with age.
True
Hematopoietic stem cells can become…
- Self-renewing stem cells
- Myeloid cells
- Lymphoid cells
- Erythroid cells
How many days to monocytes circulate in the blood?
1-3 days
What are macrophages?
Monocytes that have exited the blood, further differentiated and become fixed in the tissues
Where are Kupffer cells found?
In the liver
Where are microglial cells found?
In the brain
Where are Alveolar cells found?
In the lung
What is CR1?
A surface receptor which is complement receptor 3 for complement protein C3b
What are Fc receptors?
Bind to the Fc portion of IgG and IgE
What does Interferon-gamma (IFN-y) do and what produces it?
Activates macrophages in their resting state, produced by Th1, CD8 and NK cells
When can a macrophage become activated?
- By IFN-y cytokine
- When surface PRRs bind to PAMPs
- When it opsonizes a pathogen via its Fc or CR3 receptors
What three phases do Macrophages have?
Resting, activated, hyperactivated
What happens during the activated state of a macrophage?
Phagocytosis, killing ingested pathogens, and antigen presenting
What happens during the hyperactivated state of macrophages?
Secrete cytokines and complement proteins, kill pathogens within the macrophage, and present antigens
What is oxidative burst?
Killing pathogens within the macrophage
When phagocytosis occurs through either the Fc or complement receptors
Opsonization
The name for the antibody and complement proteins
Opsonins
List the steps of killing the pathogen inside the cell
- Increased acidity of the phagosome by pumping in H+
- Fusion of the lysosome with the phagosome
- Release of lytic enzymes and reactive oxygen and nitrogen molecules
What is oxidative burst?
Release of lytic enzymes and reactive oxygen and nitrogen molecules
What is hematopoiesis?
Production of immune cells
What is needed for lysosomes and lytic enzymes to work?
Low pH
What are the first cytokines released when a microbe is first phagocytized?
IL-1, IL-6, TNF-a, and complements
Short-lived dedicated killers that circulate in the blood until recruited
Neutrophils
What is the most predominant granulocyte?
Neutrophils
What is another name for neutrophils?
Polymorphonuclear cells
What are neutrophils made of?
3 granulocytes that contain enzymes which aid in killing
Immunopathology
Damage to neighboring healthy cells in infection
What is the life span of neutrophils?
Less than 2 days
What is the Number 1 phagocyte?
Neutrophils
What is released by neutrophils to kill pathogens?
Lytic enzymes and defensins
What are defensins?
Small peptides that polk holes in the membranes
True or False. Neutrophils do not have oxidative burst.
False, they do
What type of nucleus is found in an eosinophil?
Bi-lobed
Which isotype do eosinophils have high affinity receptors for?
IgE
Which isotype do easinophils have low affinity receptors for?
IgG
Which granulocyte is important in the pathogenesis of asthma or other chronic inflammatory diseases?
Eosinophils
Which granulocyte plays a major role in parasitic infections?
Eosinophils
What surface receptor does Basophil have?
For IgE
Degranulation
The release of contents from the granules
What do the granules in Basophils contain?
Histamine and vasodilators
Where are mast cells mostly found?
Along connective tissue and skin
Mast cells have high affinity receptors for which isotype?
IgE
What processes are platelets involved in?
Blood clotting and inflammation
Which cells are platelets derived from?
Megakaryotes
Platelets have surface receptors for what 3 cells…
- Fibrinogen (clotting)
- Complement protein C3b (inflammation)
- Cytokines (CXCR4)
What fraction of platelets circulate?
2/3
What fraction of platelets are found in the spleen?
1/3
Where are dendritic cells predominantly found?
Mostly in the skin
What do dendritic cells do after they phagocytose a microbe?
Migrate to the nearest lymphoid organ and present antigen to the T cells
Dendritic cells that have migrated to the lymphoid organ
Interdigitating cells
True or False. Only mature dendritic cells phagocytose.
False, only immature ones do
What is the most effective APC?
Dendritic cells
What is negative selection of thymoctyes
Where T cells which recognize self are eliminated
Where are follicular dendritic cells found?
In germinal centers and follicles of lymphoid organs
What is the function of follicular dendritic cells?
To present whole, unprocessed antigen to B cells to keep them activated during affinity maturation
True or False. Antigens are not internalized after they bing to FDC surface.
True
What type of T lymphocyte does CD4 become?
T helper cell
What type of T lymphocyte does CD8 become?
Cytotoxic T lymphocyte (CTL or Tc)
What is a CTL?
Cytotoxic T Lymphocyte
What functions do CD4 and CD8 serve?
- Surface markers to identify T cells
- Antigen coreceptors
- Determine which MHC class antigen presentation is recognized
What two subpopulations is CD4 divided into?
Th1 and Th2
How is Th1 and Th2 determined?
Based on cytokine production
Which cytokines favor Th1?
IL-12 and IFN-y
Which cytokines favor Th2?
IL-4 and IL-10
Th1 cells stimulate which cells?
CD8 T cells
Th2 cells stimulate which cells?
B cells to produce antibodies
And isotype switching in B cells
What three cells come from the myeloid lineage?
Granulocytes, monocytes, and macrophages
What three cells come from the lymphoid lineage?
B lymphocytes, T lymphocytes, and NK cells
What cells are members of the innate immune system?
Myeloid and NK cells
Which cells are members of the adaptive immune response?
Lymphocytes
What are granulocytes?
White blood cells (leukocytes) that are classified as neutrophils, basophils, and easinophils
Which cells constitute the majority of leukocytes?
Neutrophils
Which granulocytes are nonphagocytoxic?
Basophils
What is the best known protein in basophils and its purpose?
Histamine, to increase blood vessel permeability and smoot muscle activity
True or False. Mast cells only differentiate after leaving the blood.
True
Are easinophils phagocytoxic?
Yes
Which cells make connections between the innate and adaptive systems? They make contact with a pathogen and then communicate this pathogen to the site of infection.
Myeloid-antigen presenting cells.
