Lecture 1 - Cells of the Immune System Flashcards
What do HSC niches consist of?
What is the importance of niches?
- Osteoblasts
- Sinusoidal Endothelial Cells (blood from bone marrow)
- Stromal Cells
HSC’s would die without niches
- attracted via signal gradients
Why is it important to have a constant supply of Immune Cells (HSC)?
HSCs are multi-potent, self-renewing sources of white blood cells, red blood cells & platelets
The bone marrow provides structural & molecular support for stem cell renewal & differentiation
What cells provide support and growth factors for HSC maintenance?
Stromal Cells
What happens to HSC’s If they don’t return to circulation?
“Mobilized” to differentiate into immune cells
- thus replenish WBC’s, RBC’s, or platelets
- especially during stressful periods
What cells are of common myeloid origin? (2, 5)
RBC:
- Thrombocytes
- Erythrocytes
WBC:
- Mast cells
- Basophil
- Neutrophil
- Eosinophil
- Monocyte
- Dendritic
- Macrophages
What cells are common lymphoid progenitors?
- Natural Killer cells
Lymphocytes:
2. B Cell –> plasma cell
- T cell
- helper
- killer
What does differentiation into Myeloid or Lymphoid Cells depend on?
Stimulating Growth Factors & Cytokines
- important research tools to study immune cells
- therapeutic tools for patients
Ex: G-CSF to stimulate Neutrophils!
How do antigens from sites of infection reach lymph nodes?
VIA LYMPHATICS
Where does the thoracic duct drain into?
Left Subclavian Vein
Which of the following are specific to ONE pathogen and response results in immunological memory & protective immunity?
- Innate
- Adaptive
ADAPTIVE
What cells comprise most of the INNATE immune cells and function as the first line of defense, and responsible for carrying and presenting microbes?
Myeloid White Blood Cells!
Describe the following for Neutrophils:
- Activated Function
- Structure
- Activated Function
- phagocytosis and activation of bactericidal mechanisms - Structure
- 3-4 nuclear lobes
- AKA PMNs (polymorphonuclear neutrophilic leukocytes)
- Light pink H& E staining granules ELECTRON DENSE
Both Phagocytes & neutrophils form what when they bind the pathogen and internalize it?
Describe the next 4 steps
- PHAGOSOME
- Phagosome is acidified
- Granules called lysosomes fuse with phagosome
- Phagolysosome formed
- Enzymes & Other antimicrobial substances released & pathogen is destroyed
What can neutrophil granules also function as besides forming phagolysosome?
DEGRANULATE other antimicrobial substances
- Primary Granules
- direct/toxic activity - Secondary Granules
(specific)
- free radical formation using oxygen and enzymes
What comprises 70% of the WBC’s in the body?
Where are they normally found?
Where do they migrate during infection?
Life span?
Besides phagocytosis, what else can they participate in?
NEUTROPHILS!
- Circulating blood, not in tissues (enter during infection)
- Migrate from blood to TISSUES
- Short - lived, die after 1 round of phagocytosis
- Participate in EXTRACELLULAR PATHOGEN killing
How do neutrophils effectively immobile EXTRACELLULAR pathogens?
NETS!
- neutrophil extracellular traps