The effect of latency-associated transcript on the herpes simplex virus type 1 latency-reactivation phenotype is mouse strain-dependent

Herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) nul l mutants reactivate poorly in the rabbit ocular model. The situation in mi ce is less clear. Reports concluding that LAT null mutants reactivate poorl y in the mouse explant-induced reactivation (EIR) model are contradicted by a similar number of reports of normal EIR of LAT(-) mutants in mice. To de termine if the EIR phenotype might be mouse strain-dependent we infected BA LB/c and Swiss Webster mice with LAT(-) or LAT(+) virus and assessed EIR in individual trigeminal ganglia. Compared to LAT(+) virus, LAT(-) virus reac tivated poorly in Swiss Webster mice (P < 0.05). In contrast, the EIR pheno type of these viruses was similar in BALB/c mice (P > 0.1). Thus, LAT appea red to have a much greater impact on the EIR phenotype in Swiss Webster mic e than in BALB/c mice. The mouse strain therefore appeared consequential in the HSV-1 EIR phenotype in mice.