Effect of immunization on herpes simplex virus type 1 latent infection in the trigeminal ganglion.

Purpose: To quantify and characterize immune protection from herpes simplex virus (HSV) latent infection in mice following corneal challenge.
Methods: Mice immunized or mock-immunized and boosted in the flank with an HSV replication-deficient mutant were challenged by corneal inoculation with wild type (wt) or thymidine kinase-negative (TK(-)) HSV. At specified times post challenge, trigeminal ganglia were assayed for in vitro reactivation, latent and acute viral load (using quantitative PCR), acute infection, and cellular infiltration (hematoxylin and eosin stained sections).
Results: With wt HSV challenge infection, immunization led to reduced reactivation, significantly less latent and acute viral DNA, and no acute viral replication in ganglia, and rapid infiltration of inflammatory cells. Immunization had little effect on viral load following challenge with replication-conditional TK(-) mutant virus.
Conclusion: These results indicate that immune protection from latent HSV infection in mouse trigeminal ganglia following ocular infection can act under these experimental conditions to block acute viral replication in ganglia and is directed to antigenic targets within the ganglia.