The absence of glycoprotein gL, but not gC or gK, severely impairs pseudorabies virus neuroinvasiveness.

Penetration and propagation of herpesviruses in the nervous system require the action of several glycoproteins. To assay for a function of glycoproteins gC, gK, and gL in the neuroinvasiveness of pseudorabies virus (PrV), deletion mutants lacking one of these glycoproteins and corresponding rescuants were inoculated in the nasal cavity of adult mice. We demonstrate that the lack of gL almost prevented the virus from penetrating and propagating in trigeminal, sympathetic, and parasympathetic tracks innervating the nasal cavity, while the lack of gC and gK only slowed the invasion of the nervous system. The conclusion of this and previous studies is that only gB, gD, gH, and gL are indispensable for penetration into neurons, while gB, gH, and gL (and, in some categories of neurons, also gE and gI) are necessary for transneuronal transfer in the mouse model. The deletion of other glycoprotein genes has little effect on PrV neuroinvasiveness although it may affect the dissemination of the virus.