Stromal Keratitis Induced by a Unique Clinical Isolate of Herpes simplex Virus Type 1

Glycoprotein C (gC)-negative clinical isolates of herpes simplex virus type 1 (HSV-1) are very rare. An HSV-1 strain (TN-1), isolated from a patient with herpetic keratitis, exhibited a gC-negative phenotype. While a gC-negative mutant showed reduced pathogenicity and failed to induce herpetic stromal keratitis (HSK) in a previously reported mouse model, TN-1 induced HSK in mice comparable to RTN-1-20-3, a gC-positive recombinant virus derived from TN-1. Virus growth in eyes and brains and the mortality of TN-1-inoculated mice were equal to or higher than those of RTN-1-20-3-inoculated mice.