Intro to Immunology Flashcards
hematopoietic stem cells replicates and gives rise to
myeloid and lymphoid progenitors
myeloid progenitors controlled by GCSF
become myeloblasts and then
neutrophils
basophils
eosinophils
in the bone marrow
myeloid progenitors controlled by MCSF
become monoblasts which then become
monocytes and dendritic cells
in the bone marrow
monocytes can move into various tissues from the bone marrow and
become monocytic derived dendritic cels and tissue macrophages
Lymphoid progenitors in the bone marrow under control of IL7 differentation into
B cell precursor cells wich then mature into B cells
lymphoid progenitor cells migrate from Bone Marrow into Thymus and become
T cell precurosors which then become T cells
phagocytes include
neutrophils and macrophages
phagocytes function to
injest and destroy microbes and ger rid of damaged tissues (scavanger function)
responses of phagocytes
recruit cells to infection site
recognition and activation by microbes
ingestion of microbes
destruction of microbes
secrete cytokines to promote regulation and immune responses
mast cells, basophils, and eosinophils play a key role in
innate immune responses
protect against helminths and cause allergic reactions
common feature is cytoplasmic granules with various inflammatory and microbial mediators
mast cells
come from mast cell progenitors
do not circulate in blood as mature cells
migrate via the blood from bone marrow into tissues where they mature
part of the sentinel cell system along with DCs and macrophages
quickly repsond to environment antigens and allergens, pathogens and toxins
eosinophils are polymorphonuclear granulocytes that
defend against parasites, participate in allergic reactions
small amount in blood
large granules and small granules
snall granules have histamine and major basic protein
basic proteins involved in anti-parasitc defense
basophils
circulate in blood, very small amaont
defense against parasites
play a role in allergic reactions
dendritic cells, macrophages and B cells are
professinoal antigen presenting cells
langerhans cells are a type of DC that is a
potent APC in the epidermis
DC are part of the
innate immunity subtyped as monocyte derived (similar to macrophages) and plasmacytoid derived/IFN producing
Innate immunity is comprised of
mast cells, basophils, eosinophils, phagocytes, macrophages and dendritic cells
adaptive immunity is comprised of
B cells, T cells, NK cells
NK cells
granular lymphocytes that purge body of infected and precancerous cells
rise from bone marrow precursors, separate from B and T cell precursors
receptors have no antigen specificity
no memory made
NK cells recognize and destroy
target cells without stimulation or immunization
NK cells recognize antigens expressed
normally on host cells
if an antigen is not expressed on a host cell, the absence of the antigen activates the NK cell
NK cells have broad specificity for antigens thus making it function
like a cell of the innate immunity, but it is adaptive
cell mediated immunity
controlled by T cells which function in conjunction with APC and phagocytes
defense against intracellular bicromes (viruses and bacteria_
kill the host
helper T cells help make B cells to make high affinity Abs helping to eradicated extracellular microbes as well
Humoral Immunity
controlled by B cells who secrete Abs to prevent infections extracellular microbes
cytotoxic T cells work in
the cell mediated immunity and directly destory infected cells
T helper cells activate macroohages to kill phagocytised microbes
clonal selection
there are many distinct lymphocytes specific for different antigens
when antigen is introduced, lymphocytes with receptors for this antigen seek out and bind the antigen
after binding the antigen, they are triggered to proliferate and differentiated making clones of the cells specific for new antigen
the clones react with the ag to neutralize/eliminate it
some ag speciigc cells late in the response make memory in adaptive immunity
Fixed elements are the lymphoid organs
Primary: bone marrow and thymus
Secondary: spleen and lymph nodes, mucosal immune tissue
Mobile Immune Elements
Immune cells Humoral components (Ab, complement, acute phase proteins)
Monocytes are free in blood and become ______ in tissue
Macrophage (histiocyte)
Cluster of Differentation (CD) are
Selectively expressed on each type of leukocytes
Developed using antibodies recognizing specific antigens
T Cell CD
CD3
CD4
CD8
B cell
CD19
CD20
NK Cell
CD56
Macrophage/monocytes
CD14
Direct and indirect fluorescent microscopy
Done with anti-CD abs for ID-int leukocytes
Neutrophils are polymorphonuclear leukocytes
Segmented into 3-5 lobules
Most abundant in blood
Mediate the earliest phase in inflammatory reactions
Neutrophils are professional phagocytes
Released quickly and a lot of them
Cytoplasmic granules contain Peroxidase Lysozyme, degradation enzymes Defending
Inflammatory mediators that release cytokines, prostaglandins, leukotrienes
Live for hours to days and work for 1-2 days
Killing Mechanisms of neutrophils/phagocytes
Intra and extra cellular
Phagocytosis and ROS or antibacterial proteins
Can uses neutrophil extracellular traps (NETs) to immobilize pathogens and facilitate phagocytosis
Monocytes are the main type of
Mononuclear phagocytes IN THE BLOOD
While macrophages are in the tissues
Mature ones are released into the blood, live for a few days and then die, can survive longer during inflammation
Dendritic cells share similar characteristics to
Macrophages and are the most efficient APC
Resident Macrophages
Migrate to their areas during embryonic development from hematopoietic progenitors emerging from the yolk sac
Do tissue specific jobs
Specialized phenotype
Ex: osteoclasts, microglial cell, etc.
Monocytes derived inflammatory tissue
Monocytes migrate into tissues where a pathogen is
Differentiate into macrophages during inflammation
Invovled in inflammatory reactions, tissue remodeling
NK cells recognize and destroy variety of
Target cells without any prior stimulation or immunization
Recognize antigens self and non self
NK cells function like a cell of innate immunity
(REPEAT)
Interactions between
T cells and B cells as well as T cells and APC are critical to development of adaptive immunity
Development and maturation of T cells occurs in the
Thymus
Mature T cells is Ag stimulated, gives rise to CMI
B cells mature in the
Bone marrow
B cells activated, lead to humoral immunity and Ab (immunoglobulin)
CMI is controlled in response to
T cells as well as Ag presenting cells, phagocytes
CMI mediates host defense against
Intracellular microbes such as viruses and some bacteria
CMI function is killing of infected
Host cells that eliminates the reservoirs of infection
Some T cells help B cells make
High affinity Ab thereby contributing to the eradication of extracelllular microbes
Humoral immunity B cells secrete ab that
Prevent infections and eliminate extracellular microbes
In CMI, T helper cells activate
Macrophage to kill phagocytized T cells to directly destroy infected cells
