A homologous in vitro model to study interactions between alphaherpesviruses and trigeminal ganglion neurons.

A key aspect in the life cycle of alphaherpesviruses is their neurotropic behaviour. Sensory neurons of the trigeminal ganglion (TG) are important target cells for many alphaherpesviruses (including herpes simplex virus 1, pseudorabies virus (PRV), bovine herpesvirus 1) and constitute major sites for latent infections. The aim of this study was to develop an in vitro model that simulates the in vivo infection pattern of TG neurons by alphaherpesviruses. To this end, we developed a homologous in vitro two-chamber model using PRV and porcine TG neurons. TG of 4- to 6-week-old piglets were dissociated and cultured in the inner chamber of the in vitro model, which is separated from the outer chamber by a medium- and virus-impermeable silicon barrier. Outgrowth of axons from neuronal cell bodies in the inner chamber through the silicon barrier into the outer chamber could be observed after 2-3 weeks of cultivation. Subsequent addition of PRV to the outer chamber resulted in exclusive infection of the TG neurons by transport of virus through the axons, subsequently giving rise to productively infected TG neurons that transmitted virus to contacting neurons and non-neuronal cells in the inner chamber. Thus, we established a homologous in vitro model that mimics the natural route of alphaherpesvirus infection of TG neurons that can be used to study interactions between these viruses and this pathogenetically very important cell type.