Host Defense vs. Pathogen Offense - Ambrose Flashcards
Why do HIV + patients tend to experience GI complications?
Chronic inflammation as a result of HIV infection of CD4 Th cells leads to disruption of the gut epithelium and allows entry of enteric microbes.
Tight junctions
Membranes between cells are pressed very closely together and bound by proteins.
Desmosomes
Rivet-like cellular structure which acts to fasten cells into strong “sheets.”
Gap Junctions
Membrane proteins that form a selectively permeable pore between cells. Allows cross-talk.
Intrinsic responses to infection
Programmed cell death, autophagy, epigenetic silencing, host proteins, RNAi, CRISPRs
Cellular process hijacked by some viruses to repress host gene transcription.
Epigenetic silencing via histone deacetylation. Transcriptional activators are unable to access DNA resulting in decreased txn.
Example of a virus that utilizes epigenetic silencing during infection
HIV
Host proteins capable of preventing viral infection or replication
Host restriction factors
Host restriction factor that recognizes CpG dinucleotides and leads to degradation of viral RNAs.
ZAP
Host restriction factor that acts as a cytidine deaminase to degrade viral DNA via hypermutation.
APOBEC3
Pathogen recognition receptors present in endosomes which detect dsRNA, ssRNA, or CpG DNA
Toll-like receptors (TLR 3, 7, 8, and 9)
Major txn factors activated by TLR signaling are
NF-kB, IRF3, and IRF7
Pathogen recognition receptor which recognizes unique RNA motifs not present in host cytosol.
RIG-I
Effector function of RIG-I signaling
Activation of MAVs to promote Type I IFN production
ER-localized transmembrane protein which recognizes cytosolic dsDNA.
STING
