Immune Response to Bacteria Flashcards
Extracellular in interstial space, blood, lymph
Complement, phagocytosis, antibodies
Extracellular on epithelial surface
Antimicrobial peptides, IgA
Immune complexes often cause
Kidney dz
Anti-host antibody effect of bacteria.
Rheumatic fever
Cell-mediated immunity response to bacteria common dz
Tuberculosis
Direct mech of tissue damage
Exo/endotoxins and idrect cytopathic effects
Indirect mech of tissue damage
Immune complex, anti-host antibodies, Cell-mediated immunity
What phase does response shift from innate to adaptive
Inductive- mostly innate
Effector - mostly adaptive
What is first phase is bacteria crosses threshold
Inductive phase
1st line of defense
Epithelial layer
What causes redness
Local infection of the tissues and leakage of the epithelium
How can complement be activated that is not in blood>
Activated in tissues by macrophages
things on skin that protect
Low temp and pH
antimicrobial peptides
Normal flora
Receptors of neutrophil that are important
FcR and Cr1
Neutrophils attracted by
IL-8
TNF alpha important because
It is produced by innate cells and makes endothelium more porous
Neutrophils can kill by
ROS Antimicrobial peptides Proteinases Acid hydrolases Proteins that sequester nutrients
Activating signals produced by antibody binding to macrophage
Production of cytokines or activate complement
Macrophage will phagocytose the bacterium
If a microbe blocks NADPH oxidase or RNS
The bacteria will become an intracellular bacteria and not killed in the lysosome
Innate B-1 cells
Produced in fetal liver Few N regions because less TdT Peritoneal and pleural cavities Self-renewing Produces lots of IgM No need for T cell help Low hypermutation memory
B-1 cells main function
Produce high levels of IgM (natural antibody) in order to bind carbs non-specifically…helpful mostly for extracellular bacteria because they have polysaccharide capsule
Important organism for capsule variability
Strep pneumo
Normally would have to have a different antibody response generated for each bacteria…B-1 cells allow quicker neutralization of the bacteria
Il-17 and TNF stimulae
Inflammation
IFN-gamma stimulate
Macrophage activation (phagocytosis) Also can induce class switch to IgG
Cytoplasmic bacteira response and organisms
Chlamydia, Listeria
NK cells and CD8 cell response
Vesicular bacteria response and organisms
Legionella, Mycobacterium, Yersinia
T cell and NK cell dependent macrophage activation through IFN gamma and TNF production that activates phagolysosome
NK cells induced by and produce
IL-12 and produce IFN-gamma
T cells produce
CD40L (on surface to activate macrophage)
IFN-gamm
Cytoplasmic bacteria bind
NOD receptors and leads to NFkB activation
If something survives in the phagolysosome then
It may escape to cytoplasm and you may need a CD8 response
Intravesicular bacteria MHC presentation
MHC class 2 will activate CD4 cells that will produce IFN-gamma that activates macrophages
T cell activates macrophage by
CD40L binding and IFN gamma production
CD40L/CD40 problems means
Hyper IgM…more susceptible to pyogenic and pneumocystis
Different than AID deficient Hyper IgM
Activated macrophage
MHC class 1 and 2
NO and O2 production
Secretes IL-12 and TNF-alpha (TNF alpha is autocrine)
B7 molecules
Called an M1 macrophage
M2 macrophage
More about tissue repair and wound healing IL-4 and IL-13
IFN gamma and CD40L effects
Activate M1 macrophages to phagocytose bacteria
FasL and LT-beta effects
Induce apoptosis and kills chornically infected cells
IL-3 and GM-CSF effects
Induces monocyte mobilization and differentiation in bone marrow
TNF-alpha and LT-alpha effects
Activates endothelium
CCL2 effects
Chemokine
Neonates tend to have more of a ___ response
Th2 - not as good at intracellular
Mycobacterial infections (tuberculosis)
Dependent on Th1 - secretes IFN-gamma
Lives in phagosomes and prevents lysosome from fusing to it
Forms a granuloma
Granuloma breaks open when
CD4 cells are damaged or disappear…can be HIV, cancer, chemo, etc.
DTH response
Seen often in intracellular pathogens
Wait a period of time and get a Th1 memory T cell response to an antigen
Which cytokines inhibit classical macrophage activation and where are they from
Th2
IL 10, 4, and 13
Which cytokines produce classical activation and where do they come from
Th1
TNF and IFN-gamma
Mycobacterium leprae different response
Th1 - tuberculoid leprosy
Th2 - lepromatous leprosy (high bacterial count)
Which inhibit fusion of phagosome with lysosome
Tuberculosis, leprae, listerio pneumophi
Which survive in the phagolysosome
Tuberculosis, M leprae
Which escape phagosome into the cytosol
L monocytogenes (listeriolysin 0) and shigella
