RESULTS:
1 - 2 of 2 for "Dan Young"
Single-cycle parainfluenza virus type 5 vectors for producing recombinant proteins, including a humanized anti-V5 tag antibody
Parainfluenza virus type 5 (PIV5) can cause either persistent or acute/lytic infections in a wide range of mammalian tissue culture cells. Here we have generated PIV5 fusion (F)-expressing helper cell lines that support the replication of F-deleted viruses. As proof of the principle that F-deleted single-cycle infectious viruses can be used as safe and efficient expression vectors we have cloned and expressed a humanized (Hu) version of the mouse anti-V5 tag antibody (clone SV5-Pk1). We show that multiple different cell lines can be infected and express high levels of the Hu anti-V5 antibody with Chinese hamster ovary cells expressing 20–50 mg l−1 after 5 days when cells were grown to a density of ~1×106 cells per millilitre at the time of infection. We suggest that PIV5-based vectors may be further developed to produce recombinant proteins both in vitro and in vivo.
Persistent paramyxovirus infections: in co-infections the parainfluenza virus type 5 persistent phenotype is dominant over the lytic phenotype
Parainfluenza virus type 5 (PIV5) can either have a persistent or a lytic phenotype in cultured cells. We have previously shown that the phenotype is determined by the phosphorylation status of the phosphoprotein (P). Single amino acid substitutions at critical residues including a serine-to-phenylalanine substitution at position 157 on P result in a switch between persistent and lytic phenotypes. Here using PIV5 vectors expressing either mCherry or GFP with persistent or lytic phenotypes we show that in co-infections the persistent phenotype is dominant. Thus in contrast to the cell death observed with cells infected solely with the lytic variant in co-infected cells persistence is immediately established and both lytic and persistent genotypes persist. Furthermore 10–20 % of virus released from dually infected cells contains both genotypes indicating that PIV5 particles can package more than one genome. Co-infected cells continue to maintain both genotypes/phenotypes during cell passage as do individual colonies of cells derived from a culture of persistently infected cells. A refinement of our model on how the dynamics of virus selection may occur in vivo is presented.