Abstract
Purpose: :
We previously demonstrated that different subtypes of neurons in the trigeminal ganglion are differentially permissive for productive infection with HSV-1 in vivo, with A5+ neurons being the least permissive. The aim of the current work was to determine whether this was also true for neurons infected in vitro.
Methods: :
Cultures of dissociated adult murine trigeminal ganglia were infected with HSV-1 constructs that expressed enhanced green fluorescent protein (EGFP) from immediate-early (ICP0), early (gB) and late (gC) gene promoters at an multiplicity of infection of 30. Infected cultures were co-labeled with MAb A5 and evaluated by fluorescence microscopy.
Results: :
Neuronal cultures contained proportions of A5+ neurons similar to that seen in vivo. Expression of HSV-1 ICP0, gB and gC was first noted at 2, 3 and 4 hours post-infection (p.i.), respectively, with gene expression reaching a plateau at 6, 8 and 10 hours p.i., respectively. At 6 hours p.i. 9% of the cultured neurons were A5+, but only 1% of the ICP0 expressing neurons were A5+. At 8 hours p.i. 8% of the cultured neurons were A5+, but only 2% of the gB expressing neurons were A5+. At 10 hours p.i. 10% of the cultured neurons were A5+, but only 2% of gC expressing neurons were A5+. In contrast nearly all microglia expressed all three classes of genes.
Conclusions: :
Microglia were much more permissive for productive viral infection than neurons. As compared to the overall population of cultured ganglionic neurons, A5+ neurons are less permissive for productive infection with HSV-1. Differential permissiveness for productive infection with HSV-1 appears to be regulated at, or before, expression of the viral immediate early genes.
Keywords: herpes simplex virus • gene/expression • cornea: basic science