Vol II Ch. 3: Virus Offense meets host defense Flashcards
Anatomical and physiological barriers to infection
skin, ciliary clearance, low stomache pH, lysozyme in tears/saliva
Cells of the innate immunity
NK cells, neutrophils, dendritic cells, macrophages
Adaptive immunity components
Cyt. T cells, T cells, B cells, antibodies
All cells have ___ _____ that respond to various stresses including infection.
genetic programs;
Immune defenses refer to _____ defenses wherease ____ defenses begin with a single cell and tend to be local. what couples these responses together?
systemic; instrinsic; cytokines
What is a PAMP?
Pathogen assosciated molecular pattern
Recognition of foreign nucleic acids in mammalian cells is performed by: What does Pkr activation cause?
Pkr, TLR’s, and Rig-1; autophosphorylation, followed by phosphorylation of Elf2alpha (blocking protein syn.);
Rig-I and Pkr signal transduction activates Nf-kb, which leads to IFN (interferon) and inflammatory cytokine production
What are all the methods of NF-kappaB activation by viral infection?
signal transduction activated by virus binding receptor, viral proteins can engage signal transduction, Pkr binding dsRNA; Rig1 binding ss RNA; Ca release caused by overproduction of viral proteins in the ER
What is one of the first indications of an active infection?
cytokines in the blood
What are the three groups of cytokines?
proinflammatory; anti-inflammatory, chemokines
What cells do secreted cytokines engage?
dendritic cells, macrophages, and adjacent uninfected cells, which in turn synthesize their own cytokines
A localized viral infection often produces global effects including:
fever, lethargy, lymphocyte mobilization (swollen glands) (caused by colony stimulating factors (CSFs)), proinflammator gamma cytokines
IFN-alpha:
induces antiviral state, upregulates MHCI and MHCII
IFN-Gamma:
Activates macrophages, induces antiviral state
Tnf-Alpha
activates neutrophils, induces inflammatory response initiates fat and muscle catabolism
IFN is produced when: Cells that bind and respond to IFN create an environment where many virus are unable to propagate.
TLR bind, Rig-I binds, Mda5 binds,
Members of ______ ______ ____ family are required for sustained IFN transcription after induction. IFN can cause abrupt ____ of protein syn. What are some proteins that mediate this?
interferon regulatory protein; halting; Pkr, Ribonuclease L (10-1000X increase in conc.)
IFN-B enhancer lies in ______ free reason of genome
nucleosome
______ binds and alters DNA conformation to allow for precise binding of transcription factors
Hmg(B)
Where are PAMP receptors
Cell surface, endosomes cytoplasm
How is apoptosis a defense against viral infection?
if the cell is forced out of a quiescent state by viral regulation, this can induce apoptosis. Virus can encode gene products to modulate this though.
What is the apoptotic pathway?
It begins when cell binds proapoptotic ligand (TNF-A), which changes receptor domain to recruit death-inducing signaling proteins. This attracts procaspase 8 which activates caspase 3, which is the final effector.
