Response To Microbes Flashcards
What attracts neutrophils
IL8/CXCL8
Primary viral infection
Virus (viral capsule and internal viral proteins) infects epithelial cells by binding to a viral receptor and then replicates amongst them
What is the effect of intracellular viral infection
Activation of cytokine and cytokine receptor genes, especially type I interferons (IFNa)
Secretion of IFN-a involves __ feed back loop
Autocrine
Local effects of IFNa
Inhibition of viral gene replication
Upregulation of MHCI
With intracellular viral infection, viral peptides will appear in ___ peptide binding groove
MHCI
Viral infection results in cell ___ and viral ___
Death
Replication
Viral components activate ___ cells and locally release cytokines and chemokines amplify the activation of ___ and ___
Denrtites
Macrophages and APC
What are the dendritic cells in skin
Langerhans
What do dendritic cells do
Engulf and transport to lymph nodes via lymphatics
Cytokines and chemokines upregulate endothelial cell expression of what
Adhesion molecules such as ICAM1
Il8/cxcl8
Begin to attract cells through the endothelium towards the site of infection
Locally released cytokines such as IL1 and TNFa from macrophages
Enter bloodstream and have systemic effects of fever and arthralgia/myalgia
Dendritic cells enter lymph nodes and move to __ __
Germinal center
Local inflammation has what effect on nodes
Upregulation of adhesion molecules on HEV and lymphocytes directly enter from the blood
Many lymphocytes becomes trapped in inflamed node
SWELLING , hyperaemia, tender
Dendrites and APC are surrounded int he lymph node germinal center by _ cells
T
T cellls possessing TCR complementraty to class IIMHC molecule/viral peptide complex are activated and become what
Helper T cell
Virgin B cells acquiring viral particles through attachment to IgM or IgD process and present to ___, in turn to receive a positive growth and differentiation signals
TH2
IgM antiviral antibody is produced as a result whilst some B cells differentiate and classs switch, leading later to production of high affinity __
IgG
What surface molecules contribute to interaction of TCR with APC
CD4/MHCII and CD80/86 to CD28
CTL recognize viral peptides cross presented by _
DC
TH and CTL leave the lymph node via the draining lymphatics towards other lymph nodes, ultimately to enter the ___
Blood
When TH and CTL leave node what are their attributes
Have virus specific TCR
Up regulation adhesion molecules to allow migration into the inflamed tissues
Upregulated cytokine production
NK cells may be recruited at two points during viral infection
Early, innate antiviral role following activation by epithelium derived cytokines
Or latera stage activated by TH1 cells specific for virus
Activated CTL kill virally infected cells
Local TH1 and TH2 calls now organize the local antiviral immune response
Ok
Virus infected cells secrete and express viral proteins.
May be neutralized or removed by antibody in the form of immune complexes, which are cleared or antibody int he form of immune complexes, which are cleared, or antibody may be used to guide Fc receptor expressing NK cells
After resolution of the viral infection, what is there
Virus specific memory t and B cells reside in nodes, spleen and bone marrow
Plasma cells
Primarybacterial infection
Break in epithelial surface allows bacteria entry and proliferation
Surface __ may activate the alternative complement pathway or mannan-binding lectin pathway leading to bacterial lysis
LPS
Other complement activators
C reactive protein which binds bacterial coat polysaccharides
Mas cell granulation does what
Enhances blood flow, edema
How is increased blood flow and edema perceived
Itchiness and irritation int he inflamed area
__, __ neutrophils adhere to the vein wall as locally released chemokines and bacterial derived molecules activate both the endothelium and the neutrophils, resulting in adhesion between the two
Rolling, marginating
What bacterial products attract neutrophils
F-MLP, complement fragments like C5a and chemokines IL8/CXCL8
Opsonised bacteria are rapidly engulfed and killed by ___
Neutrophils
Dendritic cells do what
Engulf and internalize bacteria and are activated via pattern recognition receptors and migrate via the lymphatics
Bacterial antigens are processed and presented in local lymph nodes
Ok
__ cells are recruited and activated by APC in lymph node nad B cells, promoting the production of bacteria-specific antibodies
Th
Naive T cells become differentiated towards TH1 and TH2 according to the dendritic cell signals
Initially IgM is produced followed by colonial expansion and switching to other classes
Early antibacterial antibody is __
IgM
IgM is a __ complement activator
Potent
Following resolution of bacterial infection
Memory cells and production of antibody
Bacterial debris removed by local neutrophils or by antibody soluble immune complexes
