RT Journal Article SR Electronic(1) A1 Nakamitsu, Satoshi A1 Kurokawa, Aya A1 Yamasaki, Takeshi A1 Uryu, Masahide A1 Hasebe, Rie A1 Horiuchi, MotohiroYR 2010 T1 Cell density-dependent increase in the level of protease-resistant prion protein in prion-infected Neuro2a mouse neuroblastoma cells JF Journal of General Virology, VO 91 IS 2 SP 563 OP 569 DO https://doi.org/10.1099/vir.0.016287-0 PB Microbiology Society, SN 1465-2099, AB Cells persistently infected with prions continuously produce protease-resistant prion protein (PrP-res). Here, we show that the PrP-res level in prion-infected Neuro2a (N2a) neuroblastoma cells decreased to 50 % of their initial level over the first 48 h and then recovered by 96 h after seeding. The level of cellular prion protein (PrPC) also appeared to fluctuate, but did not influence the fluctuation of the PrP-res level. Prion-infected N2a cells, co-cultured with a higher number of prion-unsusceptible cells, had twice as much PrP-res as those cultured without unsusceptible cells, suggesting that cell density influences the fluctuation of PrP-res as. Direct cell-to-cell contact between cells, rather than soluble factors, was involved in the cell density-dependent increase in the PrP-res level. The cholesterol content, which is known to influence PrP-res formation, also changed depending on cell density. Our data suggest that alterations in cellular microenvironments controlled by cell density influence PrP-res formation., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.016287-0