Flashcards in Immune responses to viruses Deck (39)
What is a virus?
an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy and is able to multiple only within the living cells of a host
What is the programme viruses have to self-replication and multiplication?
gene expression; genome replication; virus assmebl; virus release and transmission
how are viruses classified?
Baltimore classificaation: type of genoma and method of replication
Give examples of dsDNA viruses?
herpes; poxvirus; adenovirus; papillomavirus
Give examples of ssDNA viruses?
Give examples of dsRNA viruses?
Give examples of negative ssRNA viruses?
Give examples of positive ssRNA viruses?
poliovirus; hep A and C
Give exaample of reverse RNA virus?
Give an example of a reverse DNA virus?
Give an example of a cytopathic virus
Give an example of a non-cytopathic virus?
What is involved in immmunity against chronic viruses?
what is involved in immunity against acute viruses?
What aer the features of barrier protection against infection in the skin?
epithelial cells joined by tight junctions; longitudinal flow of air/fluid; fatty acids; antibacterial peptides; normal flora
What are the type III interferons?
IFN delta 1,2,3
What are the functions of type I and type III IFNs?
induce antiviral repsonses and limit viral replication
Which cells are IFN receptors found on?
all nucleated cells
What do NK cells secrete to lyse cells?
perforin and granzyme B
What activates invariant and unconventional T cells?
lipids; microbiota metabolites or cytokines
What are the types of invariant and unconventional T cells?
NKT; MAIT and yd T cells
How is infection related to viral load and T cell response?
infection occurs at the same time as T cell reponse not at the peak of the viral load
How are antibodies invovled in the removal of viruses?
coat infected cell which leads to ADCC by NK cells; activate complement; opsonise for phagocytosis
Which cells are specialised for production of type I IFns?
What is the function of Th1 cells in viral responses?
provide help for opsonising and complement fixing virus specific abs that block entry into uninfected cells and activate complemetn to destroy enveloped viruses
Why do RNA viruses have a higher rate of replication than DNA viruses?
have to replicate their genoma using RNA polymerase which lacks the proofreading ability of DNA polymerase
What is the benefit of RNA polymerase for RNA viruses?
high rate of mutations allows them to change the antigenic epitopes recognised by the adaptive immune system
Aside from RNA polymerase, what other mutation mechanism do RNA viruses have?
segmented genomes which they can rearrange during viral replication
What are the major viral surface glycoproteins?
haemagluttinin and neuramidase