Host response to viral infection Flashcards
Innate/primary defenses are ______ and __________
immediate
non-specific
Adaptive immunity is ______, results in immunologicalmemory
Acquired
Cytopathic effect on virus infection from ____ or ____ cell damage
direct
indirect
Direct cell damage/death by:
DIversion cell energy Stops macromolecule syn Competition ribosome competition promotor/enhancer inhibition of interferon defense system
Retroviruses typically do not cause _______, released by cell via ________ and causes _____ infection
cell death; budding; chronic
Picornavirus causes ________ and ______, leads to fever and mucus secretion (rhinovirus) or Paralysis/death (poliovirus)
lysis; cell death
Indirect cell damage by:
integrate into viral genome
mutation in host
inflammation
host immune response
permissive cell means?
cell has machinery/components required for viral replication
Infection of non-permissive cell does not result in _______ production of viruses but may result in ____ or ________ infection
efficient
Latent/transforming
Innate defense components
Natural barriers (skin) Cells (Mac, PMN, DC, NK) Souble factors (interferons, cytokines, complement, chemokines)
Innate immunity _____ and ______ the adaptive immune response
primes
initiates
Type 1 interferon includes ___ and ____ and secreted by ______ within hours
alpha, beta (antiviral cytokines)
Infected cells
Type 2 IFN is ____,IFN produced by ____ and ____ cells and are more ____ than type 1
gamma
T and NK cells
Restricted
INF interact with ____ to signal ____ pathway - control gene transcription regulation
receptors
JAK/STAT
Type 1 IFN gulated by ______
ISRE (interferon stimulated response element)
Type 2 IFN regulated by ___
GAS - gamma activated site elements
Antiviral state (induced by IFN):
Decrease transcription Block viral replication Block cell proliferation, metabolism Increase NK cell activity (gamma IFN) Increase expression of antigen presenting molec Apoptosis (procaspase)
PRK (mediate) does what?
phosphorylates/inactivate cellular translation intiation factor - decrease protein synthesis
OAS (2-5’ oligoadenylate synthease)
activated by dsRNA
mRNA degradation
Viral antigens are found on ___, ____, ____, ____
virions
Surface of infected cells
Debris from infected cells
Peptide fragment bound to MHC molecules
Immunoglobulin can be _________ or _________ (function)
surface bound - B cell precentation to T cell
Secreted - Antibody
B cell binds antigen and stimulated to _____ which promotes _____________
divide
antibody affinity maturation
IgA function
inhibit virion/host attachment, neutralize toxin/enzyme
IgG function
INhibition fusion of enveloped virus with host
IgG and IgM can ________ to enhance _______
opsonize; phagocytosis
IgM function
coat/agglutinate viruions
IgG and IgM can faciliate in _______________________
complement lysis of enveloped viruses
Group specific implies
epitope shared by all of a virus group
Type specific implies
epitope defining virus group subset
Th cell binds to MHC Class
II
CTL bind to MHC class
I
Section of ___ IFN by helper and CTL and activate NK cells
gamma
CTL ____ virus infected cell
lysis
NK/Mac kill infected cells _____ or by ___________________
directly
ADCC - antibody - dependent - cell mediated cytotoxicity
Cell mediated response critical for _____________________-
recognizing and eliminated virally infected cells
Virus evaid host by:
antigenic variation
Immune tolerence
Restriction enzyme
Viral molecules as inhibitors/decoys
Down regulation of host proteins (MHC class I)
Infection of immunocomp hosts
Inhibition of apoptosis/cell cycle (SV40)
Class 1 downregulation tends to trigger ____ cell detection –> also express ____ of class 1 molecules.
NK
viral homolog
