immunology - processes, subdivisoons Flashcards
describe the different layers of the immune system
innante - first layer that forms barriers to prevent pathogen entry
cellular and soluble components - second layer comes into action if the barrier is broken (backup). Either neutralises threat immediately or COMMUNICATES threats to other immune cells via chemo/cytokines
adaptive immune system - this elicits a SPECIFIC TARGETED response to different threats
briefly name the functions of the immune system
recognise - threats and non-threats
react - destroy, remove or repair
regulate - turning on and off these responses
remember - allows an effective and swift response to previous threats
where do the cells of the innate immune system derive from/
all immune cells derive from hematopoietic cells
innante immune cells come from the MYELOID lineage
> macrophages/monocytes, neutrophil, eosinophil, basophil, mast cell
> also dendritic cells that link innate and adaptive immune system together by phagocytosing and antigen presenting to these cells
which immune cells are involved in parasite defence
parasites to large to be engulfed but neutrophil, eosinophil and basophils can release histidine + other mediators by degranulatons
where do the cells of the adaptive immune system arise from
all immune cells derive from hematopoietic cells
adaptive immune cells come from the LYMPHOID lineage
> B and T lymphocytes which can form immune memory, re`cognize antigens
> also there are INNATE lymphoid cells like NK that defend against viruses and cancer
describe the dange model of immuniy
immune system will respond to different threats using different chemicals and cells at their disposal
so each issue will have its own specific immune response
what is the difference between adaptive and innate immunity
innate - we are born with and involved the first and second layer of immune repsodne (barrier and cells and solbuble compentns). has a fast response
adaptive - develops and adapts to the enviroment. can form immune memory making up the third layer of immunity. makes use of lympoid lineage cells. has a specific and targeted response so slower
can you name some phsical barriers and organs in the innate immune repsosne
skin, mucous lining and cilia are physical barrier and can secrete antimicrobial elements or expel pathogen by wafting (mucocicilary escalator)
hostile environment is stomach acid as well as sweat and urine to expel the pathogen or at least weaken it due to low pH
lungs we can cough and sneeze to expel pathogen
can you name some chemical barriers in the innate/early induced phase of immunity
lysozymes in tears and sweat can degrade the bacterial cell walls and also skin secretes antimicrobial factors
> e.g psoriasin and protectin
lysosomes are part of the oxygen independent degrafation pathways
how is the skin adapted to protect us from pathogens?
so the epithelial cells can produce alpha and beta defensins and s100 proteins which can target invading pathogens
also epithelial cell are dead and keratinised and regualrly shed so helps with removal of pathogen
what is the role of surfactant in immunity?
surfactant is secreted by type2 alveolar cells and contain proteins like surfactant protein A.B,C which can mark pathogens (act as. Opsonins) making them easier to engulf
lungs also have alveolar macrophages too which can phagocytose to elimiate pahogen
can you name some soluble mediators
cytokines, chemokines , mucins antimicrobial peptiles like s100, defensins and
histidine is a chemcisl mediator, how does it help in immunce cell recruitment?
histidine can dilate blood vessels so more WBC can be recruited from the circulation
Secreted by basophils via granule degradation
what is acytokine and what is a chemokine
cytokines are secreted proteins which are invovled in cell growth, differentioation and can help to traffick cells and develop immune tissue in immunity
chemokines are a subtype og cytokine which is invovled in chemotaxis to recruit immune cells
how do macrophages respond in an immune respinse?
they can become inflammatroy macrophages so are larger, express hydrolytic enxymes, have an enhanvced phagoctyotic abiblity.
this dissipates as the inflammation is resolved
describe features of cytokines. how do they work?
they are pleiotrpic so can act on more than one cell type but also show redundancy as mutliple ones can have the same effect
act synergisitcally or antagonisisically with each other
they will activate signal transcution cascades to activate, regulate or amplift the immune resposne
besides chemotaxis, what else can cytokines do?
well they can promtoe wound healing, angiogenesis, metastasis and cell trafficking too!
there are 4 families of cytokines, can you name then>
naming is based on the location of the *conserved cytosinse* aa on the N terminus C C-C CxC CxxxC
describe the actions of the main cytokines
tnf-alpha and IL-beta - can bind to immune and non immune cells. activate vasclar endothelium cells to help migration of immune cells from blood
IL-6 - proinflame but also antiinflame, activates lymphocytes to increase antibody production
> both have a negative feedback effect on hematopoeric cells to increase neutrophil differentiation