Vishy - Innate Defenses Flashcards
Components of innate immunity include:
- skin: made up of 2 layers, epidermis and dermis
2. mucous membranes
The outermost layer of epidermis is called ___ ___ which is made up of dead cells and is formed from _____ present in underlying layers of epidermis. Sebaceous glands produce sebum which maintains a low pH to prevent colonization of microbes.
stratum corneum; keratinocytes
Vagina is colonized by ____which produces lactic acid which maintains pH of 4.5 which prevents colonization of fungus. Stomach produces ____ secrete stomach ___cells secrete alpha defensins which inactivate bacteria.
lactobacillus; HCL; panneth
The respiratory cells secrete ___ defensins which has antimicrobial effects similar to alpha defensins
beta
What are cells of the innate defense system
- Neutrophils
- Monocytes
- Macrophages
- Dendritic cells
- Natural killer cells
Phagocytic cells recognize microbial infection using pattern recognition receptors such as ____ ___ ____ and complement receptors. TLR-2 recognize _____ and ____acid. TLR-4 recognize ___.Phagocytosis occur through special areas called ___ ___ pits
toll like receptors; peptidoglycan; lipotechoic; LPS; clathrin coated
Phagoctyes kill intracellular organisms via 2 pathways:
- Oxygen dependent:
- Generation of reactive oxygen intermediates
- Generation of reactive nitrogen intermediates - Oxygen independent:
- Generation of antimicrobial peptides
- Fusion between phagosome containing microbes with lysosome.
How are reactive oxygen intermediates produced?
NAPH oxidase reduces molecular oxygen to form superoxide molecule which serves as precursor for rest of reactive oxygen species. Superoxide molecule reacts with another superoxide molecule to form hydrogen peroxide (dismutation rxn). Hydrogen peroxide kills microorganisms. But some are not resistant to it. So, it then combines with chloride ions in the presence of myeloperoxidase to produce hypochlorous acid. This can react with hydrogen peroxide to form singlet oxygen.
Macrophages can’t generate ____ acid and singlet oxygen bc they dont have myeloperoxide. But they can generate superoxide and hydrogen peroxide. , and nitric oxide.
hypochlorous
____converts argenine to nitric oxide used by macrophages. ____ is produced by CD4 T cells and ____ is produced by macrophages. IFN-gamma activates macrophages to control the infection and induce iNOS in macrophages and mobilize NKs
iNOS; IFN-gamma; TNF-alpha
Pathway of oxygen indpendent include the following:
- lactoferrin
- lysozyme
- alpha defensins (neutrophils only)
- DNAase and RNAase
During infection, cells release ____, a major cytokine
interferon (IFN)
What are the two types of interferons
- Type I: IFN-alpha and IFN-beta (when infected with virus)
2: Type II: IFN-gamma
____ is released by the virus infected cells and induces uninfected cells to produce ____which has antimicrobial effects.
IFN-alpha; PKR
FIbroblasts secrete ___interferon. FDA approved alpha IFN is used as an antiviral drug against hepatitis ____ and also to treat genital warts
beta; C
What are the four cardinal signs of inflammation
- pain
- redness
- swelling
- increase in temp and fluid accumulation
If gram negative infection , LPS is recognized by ____. Then there is downstream signaling which leads to activation of _____and induces transcription of ____, ___ and TNF-alpha. But if too much production of these it can lead to septic shock, cachexia (muscular waisting), anorexia, and inflammation
TLR-4; NFkB; IL-1; IL-6
what are characteristics of septic shock
- hypotension
- disseminated intravascular coagulation
- inflammation
NO synthase enzyme exists in 3 forms:
eNOS: endothelium
nNOS: neurons
iNOS: expressed in macrophages and smooth muscle
Nitric oxide can
- kill pathogen
2. decrease blood pressure
describe the clotting process
- ex: TNF-alpha activates tissue factor on macropharages–>7–>10–>prothrombin–> thrombin ->fibrinogen –> fibrin
COmplement are serum proteins. ___ activates the alternate pathway of complement activation.
LPS; activation of C3–> 5, 6, 7, 8, 9 –>6-9 form membrane attack complex which binds to cell wall of bacteria leading to rupture of bacteria.
B participates in chain reaction to form membrane attack complex. ___ serves as an anaphylotoxin inducing mast cells and basophils to release ___ which is how inflammation occurs.
c5a ; histamine
TNF-alpha also induces the expression of P selectin ____selectin and ____. Explain what happens after
E- selectin; ICAM; immune cells will bind here and since vasculatre is permeable they would be able to go to extravascular site and cause inflammation.
