TY  - GEN
N2  - Lentiviral vectors (LVs) are vectors of choice for many gene therapy applications since they mediate long term gene expression and can transduce dividing and non-dividing cells. Recently, efficient targeting of LVs pseudotyped with the measles virus (MV) glycoproteins has been reported. However, MV antibodies in patients might limit the clinical use of these vectors. Thus, aim of this study was the development of targeted LVs pseudotyped with the glycoproteins of Tupaia paramyxovirus (TPMV). Since this animal paramyxovirus does not infect humans, no TPMV antibodies in patients are expected. For efficient incorporation in LVs, the TPMV glycoproteins, the hemagglutinin (H) and fusion (F) protein, were modified by truncation of their cytoplasmic tails. Targeting was achieved by displaying a single-chain antibody against the B cell surface marker CD20 on the H protein. The modified proteins were biochemically characterized and tested for their functionality. Unexpectedly, it was observed that an additional proteolytic cleavage of the F protein occurs during activation, resulting in the fragments F1a, F1b and F2. The newly identified fragment F1a was detected in virions and in supernatant of transfected cells. The F1a/F1b cleavage site was mapped and a cysteine protease was identified as likely activating protease. The data indicate that F protein processing is more complex than expected. After characterization, the modified TPMV glycoproteins were screened in all combinations for their ability to form functional pseudotyped LVs. Most efficient pseudotype formation was achieved with CT truncations of 80 amino acids (aa) for H (H?80?CD20) and 32 aa for F (F?32) (titers ~ 106 t.u./ml). The resulting vectors selectively transduced CD20-positive cells in a mixed cell population. Furthermore, they mediated efficient gene transfer into activated and quiescent primary human B cells. Neutralization assays showed that TPMV-pseudotyped vectors were not neutralized by human sera containing MV antibodies.  In conclusion, it was demonstrated that targeted LVs pseudotyped with TPMV glycoproteins can be generated and escape neutralization by MV antibodies. Remarkably, the vectors are able to efficiently transduce even quiescent B cells. Hence, they might be a valuable vector choice when systemic application of targeted lentiviral vectors in humans is required. 
TI  - Targeted lentiviral vectors pseudotyped with the Tupaia paramyxovirus glycoproteins
A1  - Enkirch, Theresa
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/12946/
KW  - lentiviral vector 
KW  -  pseudotyping 
KW  -  gene therapy 
KW  -  Tupaia paramyxovirus
Y1  - 2011///
ID  - heidok12946
AV  - public
ER  -