Basophils, Eosinophils, and Monocytes Flashcards
Basophils
- matures in BM
- basophilic granules (lots so difficult to observe maturation)
- bilobed nucleus
circulate in blood until directed to inflamed tissue - 60-hour lifespan; anti-apoptotic
this is critical for basophil differentiation
IL-3
contributes to long lifespan (60 hrs)
these initiate and mediate allergic response
- basophils
- receptors for IgE
- type I hypersensitivity
these regulate immune response and releases cytokines to regulate T-helper cells
basophils
these assist eos in control of helminth infections
basophils
Basopenia
low basophils (disorder); hard to assess due to the low number of basophils
eosinophils
- bilobed nucleus; azurophilic granules
- IL-5 critical for proliferation and survival
- concentrated at mucosal surfaces
- remains in circulation for about 18 hrs
- reside in tissues for 2-5 days
T or F. eosinophils act as antigen presenting cells
T!
Charcot-Leyden protein
- eosinophil
- lysophospholipase
- hydrolyzes different types of phospholipid membranes
eosinophil cationic protein
destroys membranes
major basic protein of eosinophilic granules
disrupts membranes
eosinophil peroxidase
generates toxic radicals
histaminase
produced by eos; inhibits histamine
10% of leukocytes
monocytes
monocytes are derived from…
granulocyte-monocyte progenitor cells
housekeeping functions of monocytes
- remove debris
- destroy senescent RBCs and stores iron
- production of proteins, enzymes, interleukins, complement, growth factors, etc.
monocytosis
caused by inflammation, infections, hypersensitivity, tissue repair, neutropenia, drugs, stress, malignancies
monocytopenia
- rare ; other cytopenia involved
- aplastic anemia, EBV chemo, or steroid therapy
Niemann-Pick disease
- lipid storage disease of monocytres (def of sphingomyelinase)
- accumulation of sphingomyelin in macrophages giving foamy cytoplasm with lipid filled vesicles
Basophil granules
- histamine
- chondroitin sulfates
- eosinophilic chemotactic factor
- prostaglandin D2
- leukotrienes
- interleukins
Gaucher disease
- monocyte disorder
- lysosomal lipid storage
- def in B-glucocerebrosidase
- glucocerebroside accumulates in macs giving cytoplasm a wrinkled/striated appearance
largest reservoir of monocytes
- red pup of spleen
- releases them in response to tissue damage
T or F. basophils are phagocytic
F! non-phagocytic
basophil granules
- histamine = hypersensitivity + inflammation
- chrondroitin sulfates = heparan sulfate
- eiosinophilic chemotactic factor
- prostaglandin D2 (vasodilation)
- leukotrienes (mediates inflammation)
- interleukins
type I hypersensitivity
- IgE mediated
- first exposure = B cells produce IgE which bind to mast cell and basophil membranes
- second = antigen binds IgE causing cross-linking and degranulation
- symptoms = vessel dilation, airway constriction, itching, mucous secretion
Basophilia
- most common: MPN
- allergic rhinitis
- hypersensitivity to food or drugs
- chronic infections/inflammatory conditions
- bee stings
Mast cells
- lots of granules and dispersed chromatin
- not “true” leukocytes
> derived from hematopoietic precursors
> mast cell progenitors travel from BM to tissues to mature - involved in both innate ad adaptive immunity (effector cells in allergic reaction)
where are mast cells found?
- skin and mucous membranes (skin, intestines)
- long lifespan in tissues
eosinophil functions
- immune regulation: acts as antigen-presenting cells
- hypersensitivity: activation + regulation of basophils and mast cells, release IL-8 to activate neuts and T-cells, dampens effect of monocytes and basophils (via histaminases)
- regulate inflammation: inactivate substances released by basophils and mast cells
- destroy helminthic paasites
- allergic disorders (asthma)
Eosinophils release this to activate neutrophils and T cells
IL-8
eosinophil phagocytosis
- kills parasites too large to be phagocytosed
- via IgE complement coating the parasite
- T cells and basophils release interleukins to attract eosinophils
- eosinophils bind tightly to parasite and release granular contents
- frustrated phagocytosis
eosinophilia
- allergies
- parasitic infections
- drugs reactions
- malignancies
- skin disorders
- pulmonary disorders
major cytokine causing proliferation of monocytes
macrophage colony-stimulating factor
T or F. monocytes are released directly into circulation once mature
T!
T or F. Monocytes have a marginating and circulating pool in the peripheral blood
T!
- remain in circulation for 3 days
- responds to infection/inflammation immediately
- becomes resident cells
- lifespan ranges from hours (inflammatory macs) to 21 days (Kupffer cells)
Monocyte functions in innate immunity
- recognize bacterial pathogens
- produce inflammatory cytokines
- phagocytosis
- synthesize nitric oxide (Cytotoxic)
adaptive immunity functions of monocytes
- macs and dendritic cells are APCs
- activate B and T lymphs
