extra info Flashcards
what is the initiation of apoptosis
- binding of a death ligand (e.g. TNFR1 or Fas) on the cell surface, e.g. direct binding of T cells or NK cells, or tumour necrosis factor (TNF) secretion of immune cells 2. Membrane disruption of perforin, then intracellular injection of granzyme B by cytotoxic T cell 3. Release of pro-apoptotic proteins, e.g. cytochrome c, from leaky mitochondrial membranes, a process largely regulated by pro- and anti- apoptotic proteins of the Bcl-2 family 4. p53, a gatekeeper gene in the cell cycle. p53 protein instigates apoptosis if there is a failure to repair DNA damage
what are the main cells involved in the innate immunity
neutrophil polymorphs, eosinophils, mast cells and basophils and monocytes and macrophages
what are neutrophil polymorphs
70% of the peripheral blood leucocytes,
where are neutrophil polymorphs produced from
myeloid precurors in the bone marrow
how do neutrophil polymorphs kill invaders
by phagocytosis and release of their granules
what do neutrophil polymorphs contain
lysosyme, reactive oxygen species, myeloperoxidase and other harmful agents
how long do neutrophil polymorphs usually live
5 days
how long do neutrophil polymorphs live once they are in the blood
10 hours
what are eosinophils derived from
the myeloid lineage
what do the eosinophils granules contain
histamine, heparin, major basic protein and bactericidal eosinophil cationic protein and others
do eosinophils phagocytosis things
no
how do eosinophils act against pathogens
release their granules and important against large pathogens
what are eosinophils recruited by
IL-5
what secretes serotonin in the tissues
mast cells
how do mast cells release serotonin
by degranulation
