Latent Herpes Simplex Virus 1 Infection Does Not Induce Apoptosis in Human Trigeminal Ganglia

ABSTRACT Herpes simplex virus 1 (HSV-1) can establish lifelong latency in human trigeminal ganglia. Latently infected ganglia contain CD8 + T cells, which secrete granzyme B and are thus capable of inducing neuronal apoptosis. Using immunohistochemistry and single-cell reverse transcription-quantitative PCR (RT-qPCR), higher frequency and transcript levels of caspase-3 were found in HSV-1-negative compared to HSV-1-positive ganglia and neurons, respectively. No terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay-positive neurons were detected. The infiltrating T cells do not induce apoptosis in latently infected neurons.