Cell-cell interaction appears to represent a pivotal factor for susceptibility of adult canine schwann cell-like brain glia to canine distemper virus infection in vitro

Abstract

Recently, we reported the preferential infection of a novel glial cell type from adult canine brain, termed Schwann cell-like brain glia (SCBG) with canine distemper virus (CDV). To further characterize virus-cell and cell-cell interactions, SCBG in purified and mixed brain cell cultures was infected with different CDV strains. Cell cultures were infected with the attenuated CDV-Ond, CDV-2544, CDV-OndeGFP, CDV-R252 and the mustelid virulent CDV-5804PeGFP strain. Cytopathic effects (CPEs) and the percentage of infection were monitored daily at 3 and 10 days post-infection (dpi), respectively. At 10dpi, the CDV strains induced mild to moderate and severe CPEs in purified SCBG and fibroblasts, respectively, while both cell types displayed mild to moderate CPE in mixed brain cell cultures. Comparative analysis of CDV infection revealed that the virulent CDV-5804PeGFP strain caused a delayed infection of SCBG in mixed culture. Independent of the virus strain, infection of purified SCBG was significantly compared to mixed brain cell cultures. Contrary to this, fibroblasts were infected to the same extent in both culture conditions. There are two main findings of the present study. Firstly, CDV strains displayed differential infection of SCBG in purified cultures. This is a confirmation and extension of previous findings in mixed culture. Secondly, a dramatic decrease in the extent of CDV infection was observed after purification of SCBG. This was independent of the CDV strain used and implies that undetermined interactions between SCBG and other cells, eliminated during purification, crucially determine the susceptibility of SCBG to CDV infection in vitro.