Syncytium inducing strains

One of the first standardized phenotypic tests was the HeLa CD4+ plaque reduction assay (4). Although this assay is easy to perform, inexpensive and has a high reproducibility, it is rather labor-intensive and is only suitable for syncytium-inducing (SI) strains. Most patient isolates contain nonsyncytium-inducing (NSI) strains or a mixture of SI and NSI strains. The necessary in vitro cultivation of patient isolates to obtain a high-titer standardized Sl-inocu-lum selects for a subpopulation of SI variants. 

Beisser, P.S., Grauls, G., Bruggeman, C.A., Vink, C 1999. Deletion of the R78 G protein-coupled receptor gene from rat cytomegalovirus results in an attenuated, syncytium-inducing mutant strain. J. Virol. 

Glushakova, S., Baibakov, B., Zimmerberg, J., and Margolis, L. B. (1997) Experimental HIV infection of human lymphoid tissue correlation of CD4+ T cell depletion and virus syncytium-inducing/non-syncytium-inducing phenotype in histocultures inoculated with laboratory strains and patient isolates of HIV type 1. AIDS Res. Hum. Retroviruses 13, 461-471. 

Schols D, Pauwels R, Witvrouw M, Desmyter J, De Clercq E. Differential activity of polyanionic compounds and castanospermine against HIV replication and HIV-induced syncytium formation depending on virus strain and cell type. Antiviral Chem Chemother 1992 3 23-29. 

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