last min facts Flashcards
macrophages sit
under the skin
role of thymus and spleen
primary lymphoid organs
thymus - nursery for maturity
spleen - filters blood passing through and removes toxins
lymphoid lineage cells
NK
B
T
DC
are immune cells mobile
yes
myeloid lineage cells
macrophage neutrophil eosinophil basophil mast cell
erythroid lineage cells
erythrocyte
megakaryocyte
components of serum
plasma minus clotting factors
physioloigcal effects of cytokines released by macrophages
vasodilation and icnreased permeablity
redness
swelling
heat
features of innate receptors
limited diversity
encoded in germline
recognise structures common to different pathognes
features of adaptive receptors
generated by gene recombination
massive diversity
recognise structures unique to different microbes
2 examples of immune failure
spanish flu 1918
TGN1412
what eliminates self recognition
clonal deletion
adaptive soluble receptors
antibodies
adaptive cell receptors
T cell receptors
B cell receptors
receptors on macrophages
scavenger
complement
PRRs
indirect innate activation
PAMP binds to PRR –> phagocytosis
direct innate activation
bacteria are coated with antibodies
recognised by Fc receptors
example chemokine
IL-8
cytokine receptor
JAK/STAT
transendothelial migration moves what from where to where
moves neutrophils and imune cells from blood vessel through epithelium into adjacent connective tissue
chemotaxis –> followa gradient of chemokines
role of fMLP
bacterial peptide chemoattractant –> recruits neutrophils to inflammatory cites by binding to receptors on outside of neutrophil
adhesive cell surface molecules important for
migration and communication
dendritic cells cells in mucosal epithelium of gut
specialised process extend between cells
prevent inflammatory response against harmless gut bacteria
receive information about antigens
then present them on outside to TCRs on naive T cells
effector T cell
triggered to kill/activate cell displaying the same MHC antigen
MHC I
expressed by all body cells
monitors cytoplasm of cells
expresses antigen to CD8 T cells
where do viruses replicate
cytoplams
MHC II
expressed only on immune cells
monitors vesicles of the endosomal/lysosomalpathways
express antigen to CD4 T cells
importance of vesicles of endosomal and lysosomal pathways
contain internalised antigens from extracellular pathogens
activated CD8 T cells produce
perforins - pores in membranes
granzymes - proteases –> apoptosis
how are B cells activated
recognised antigen displayed by MHC II
internalise antigen and deliver to endosomal compartments
what happens when a B cell is activated
B cell proliferates and differentiates into an antibody secreting plasma cell
components of humoral immunity
secreted antibodies
complement proteins
antimicrobial peptides
clonal expansion
B cell producing correct antibody for antigen is activated and multiplied
how are classes of antibody distinguished
by number of Y units and by type of heavy chain
what binds to secretory component
polymeric Ig receptor on epithelial cells
pIgR binds to secretory component of IgA - what happens?
stimulates uptake of antibody and transcytosis of IgA through epithelium into lumen side of gut
once IgA has docked onto Fc alpha/mu receptor - what happens?
opsonisation of pathogen phagocytosed by Fc alpha/mu receptor pathogen destroyed in phagolysosome signalling via ITAM phosphorylation of tyrosines --> recruitment of Syk/Zap-70
examples of collectins
surfactant proteins A and B
MBL
MASP involved in which pathways
lectin activation pathway of complement
importance of C3b being bound to bacterial surface
response is localised so no collateral damage
cytokines promoting anti-viral immunity
interferon alpha and beta
cytokines activating endothelial cells and causing fever
IL-1
TNF-a
cytokines causing proliferation of antibody producing B cels
IL-6
diseases where host cells become infected and need to be destroyed by CD8 T cells
salmonellosis
tuberculosis
results of CD4 T cell activation
macrophage activation
inflammation
maturation of antibody response
virulence factors of candida albicans
reproduces asexually
dimorphic
role of dectin-1
mediates recognition of B-1,3-glucan and B-1,6-glucan and zymosan from fungal cell walls
what is dectin-1
c-type lectin carbohydrate recognition domain
found on surface of DCs
what does MyD88 stand for
myeloid differentiation factor 88
similarities of MyD88 and Syk
MyD88 enhances TLR signalling
Syk enhances dectin-1 signalling
how is MBL coupled to complement pathway
MASP
MASP =
mannose binding lectin associated serine protease
larval stages of helminths
nematodes
trematodes
cestodes
importance of antigenic variation
underlies capacity of organisms to survive in a host
– allows organisms to escape host defences
VSG stands for
variant specific surface glycoprotein
how do cytopathic viruses lyse cells
induce autophagy or apoptosis on exit of cell
latent virus
infects cells but lies dormant
only activated when immunity wanes
produces infectious virions when activated
mediators of viral immunity
innate - type 1 interferons, complement, NK
adaptive - neutralising antibodies, CD8 T cells
antibody dependent killing direct and indirect
indirect - via complement, antibodies pepper outside and activate classical
direct - Fc receptors, directly to neutralising Igs
NK cell mediated ADCC
Fc receptors on surface of NK cells
bind to Ig as virus leaves infected cell
kill using perforins and granzymes
PCP
pneumocystic pneumonia
HIV protein structures
gp120 - docking glycoprotein
gp41- transmembrane glycoprotein
HIV causes loss of CD4 t cells - why is this bad
no helper t cell activities
no maintenance of CD8 T cells
no antibody response of B cell
bird/avian viruses prefer
intestinal cell receptors with a-2,3-sialic acid linkage to galactose
Which immunoglobulin isotype accumulates in the foetus before birth?
IgG
which immunoglobulin is secreted in breast milk?
IgA
PET =
positron emission tomography
