1.3 Respiratory Viruses Flashcards
- family orthomyxoviridae
- ssRNA, enveloped viruses with a helical nucleocapsid
- genome of 7-8 segments
- types A, B, C, D
- HA, NA, M2
influenza viruses
in influenze viruses, facilitates attachment to sialic acid rececptor
hemagglutinin (HA)
in influenza virus, facilitates release of infectious virus from cells
neuraminidase (NA)
in influenza virus, necessary for virus entry
M2 protein
influenza pathogenesis?
virus deposited on the respiratory tract epithelium, attaches to and penetrates columnar epithelial cells
normally prevents attachment of influenza virus to columnar epithelial cells?
specific secretory IgA antibodies against hemagglutinin, mucoproteins, and mucociliary apparatus
key cytokine storm mediators in influenza?
IL-6, TNF-alpha, Interferon a/b, IL-1 a/b, IFN-gamma
- point mutations in antigenic sites reduce or inhibit binding of neutralizing antibodies
- generally results in local epidemics
- occurs in influenza A and B
antigenic drift
- a sudden, major change in the antigenic structure of HA and/or NA
- results in pandemics because the populations don’t have neutralizing antibodies against the new virus
- occurs only in influenza A
antigenic shift
- two different viruses infect the same cell
- new strains emerge
genetic reassortment influenza
H1N1 resembles an _____ origin virus, reappeared as Russian flu in 1977
avian
in influenza immunity, which are the protective antigens of the virus?
HA and NA glycoproteins
influenza vaccines are ________ and given ________, the purified virus is split with a detergent and components purified
inactivated, intramuscularly
- enveloped, pleomorphic virions
- contain non-segmented, (-) ssRNA
- syncytia inducing viruses
paramyxoviruses
includes measles virus, mumps, respiratory syncytial virus, metapneumovirus
paramyxovirus
attachment protein of paramyxovirus and mumps?
HN protein
attachment protein in measles?
H glycoprotein
attachment protein in RSV?
G glycoprotein
all paramyxoviruses have a ________ protein, allows syncytia to form
F (fusion)
replication of paramyxovirus?
fusion of viral and cellular membrane through action of F protein, makes positive transcript, mRNAs translated to protein, assembly and release at plasma membrane
paramyxoviruses cause fusion of neighboring cells, mediated by F protein of virus
syncytia formation
measles rash caused by a ______ response against infected endothelial cells
T cell
-measles virus infects cells of the ______ tract, then spreads ________
respiratory tract, systematically
essential to control infection in measles, antibody is not sufficient
cell mediated immunity