Flashcards in EBV Deck (62)
What is essential for virus genome replication and segregation of EBV?
What type of virus is EBV?
gamma-1 herpes virus (HHV4)
What is the virion of EBV?
What is a virion?
complete infective form of a virus outside the host cell
What is the tropism of EBV?
infects B cell and sometimes epithelial cells and T cells
Where are latent EBV found?
memory B cells
Where is EBV found after lytic replication?
What malignant diseases is EBV implicated in?
B cell lymphomas; nasopharyngeal and gastric carcinomas
What type of B cell with EBV infect in vitro?
any resting B cell
what is the effect of EBV infection of a esting B cell?
drive out of resting state to become an activated proliferating lymphoblast
How many gene programmes does EBV have?
What are the 4 gene programmes that EBV has?
1- used to produce infectious virus; other 3 are associated with latent infection
What are hte 3 latent gene programmes in EBV?
growth programme- all 9 known latent proteins are expressed; default programme- restricted set of 3 latenet proteins; latency programme- few if any latent genes are expressed
What determines the gene programme used by EBV?
location and differentiation stateo f hte infected B cell
What is persistent infection by EBV characterised by?
stable numbers of latently infected B cells in the blood and steady shredding of infectious virus into the saliva
What immune response accompanies the persisten infection of EBV?
stable levels of CTLs and serum antibodies to lytic and latent-stage proteins
What does a simple mutation in SLAM-associated protein restul in?
diverts EBV from benign persistence to acutely aggressive X-linked lymphoproliferative disease
Which gene programme does EBV use to activate B cells?
Which gene programme does EBV use to change activated B cell into memory cell?
What are the 3 viral proteins expressed in the default programme?
EBNA1; LMP1 and LMP2A
What are LMP1 and LMP2A?
multiple membrane-spanning molecules that lack significant extracellular domains which act as active ligand-independent receptors
What is the key function of LMP1 and LMP2A?
possess the signalling capability to rescue an activated B blast in to the memory B ecll pool
What receptor does LMP1 share functional homology with?
CD40- demonstrated by experiments showing that the signalling domains are interchangeable
What receptor does LMP2A share similatirty to?
same ITAMs found in the alpha and beta chains of the BCR, associates with Lyn
How do EBV-infected cells enter the memory pool?
shutting down expression of all viral latent proteins- latency transcipriont programme
What is the result of signalling from both CD40 and LMP1?
rescue B cells from apoptosis and drive proliferation
Where in the body is EBV active?
naeopharyngeal lymphoid system e.g tonsils
Where in the body is EBV dormant?
What protein is the master transcirption factor in the growth programme of EBV?