The immune system Flashcards
The immune system consists of what?
cells, tissues and organs
Describe hematopoiesis
A multipotent hematopoietic stem
cell (HSC) → progenitor cells (common lymphoid
progenitor + common myeloid progenitor) →
more specific progenitors →
Lymphoid lineage: consists of
T cell, B cell, NK cell, ILC (agranulocytes)
Myeloid lineage: consists of
Erythrocyte, platelets,
polymorphonuclear leukocytes
(PMN) (or Granulocytes: neutrophil,
eosinophil, basophil, mast cells);
monocyte and immature DC
(agranulocytes)
What are innate lymphoid cells, do they express antigen-specific receptors?
Innate lymphoid cells (ILCs)
are immune cells that belong to
the lymphoid lineage but do
not express antigen-specific
receptors.
Innate lymphoid cells (ILCs) function and what do healthy individuals express
Function in innate immune
responses to secrete cytokines to
regulate homeostasis and
inflammation
○ Healthy individuals: 0.01%~0.1%
circulating lymphocytes express a
ILC phenotype
White blood cell (WBC) or
leukocyte =
White blood cell (WBC) or
leukocyte = blood cells –
RBCs – platelets
- Granulocytes:
- Agranulocytes:
The myeloid lineage comprises most of the cells of the innate immune system such as
macrophages, eosinophils, dendritic cells, basophils, neutrophils, and mast cells.
Describe how NK cells look, which systems they’re involved in, function, and how they are unlike lymphocytes
Natural killer (NK) cells: large, granular, lymphoid-like cells with important functions in innate immunity (especially against intracellular viral infections), being able to kill other
cells. Unlike lymphocytes, they lack antigen-specific receptors.
Macrophages and neutrophils are primarily what type of cells? What type of pathogens do they destroy? innate or adaptive immunity?
Macrophages and neutrophils are primarily phagocytic cells that engulf
pathogens and destroy them in intracellular vesicles, a function they perform in both innate and adaptive immune responses
Describe dendritic cells when they are mature and immature. What is the function?
Dendritic cells are phagocytic when they are immature and can take up
pathogens; after maturing, they function as specialized cells that can leave the site of infection to present pathogen antigens to T lymphocytes in a form they can recognize, thus activating T lymphocytes and initiating adaptive immune
responses.
Describe macrophages, what do they inhabit, eliminate, and present?
are long-lived cells, inhabit specific organs and body areas,
eliminate dead cells or other debris from apoptosis, and can also present antigens
to T lymphocytes and can activate them.
● The other myeloid cells are primarily secretory cells that release the contents of
their prominent granules upon activation via antibody during an adaptive immune
response.
are thought to be involved in attacking large antibody-coated
parasites such as worms
Eosinophils
are also thought to be involved in anti-parasite immunity.
Basophils
are tissue cells that trigger a local inflammatory response to antigen
by releasing substances that act on local blood vessels
Mast cells
