ch includes both the Hb-restricted CD4 and Kd-restricted CD8 immunodominant epitopes derived from glycoprotein D , were used to evaluate anti-HSV1 T-cell responses in BALB/c mice. Peptide stocks were prepared in DMSO at 1022 M concentration, stored at 220uC, and diluted in RPMI 1640 before use. In Vivo titration of wild-type HSV1 and live attenuated HSV1-Tat or HSV1-LacZ Animals were handled according to RU 58841 site European and Institutional guidelines. The lethal dose of wild-type HSV1 was determined in both BALB/c and C57BL/6 female mice, since susceptibility to HSV1 infection varies according to mouse gender and strain. To bring the mice to the same oestrous stage and render them more susceptible to HSV infection, 2 mg/100 ml of Depo-Provera was injected subcutaneously into the neck of 8-week old female BALB/c and C57BL/6 mice, one week before challenge. Mice were then inoculated intravaginally with a range of 26104 to 26108 pfu/mouse of wild-type HSV1, LV strain to determine the lethal doses for challenge experiments. Before injection, the virus was thawed on ice, sonicated for 5 s, and 
stored on ice. Mice were anaesthetized with 5% isofluorane to allow scraping of the vagina with a pipe cleaner and then inoculated with the purified virus using a pipette tip. After infection, mice were observed daily to monitor the appearance of any local and/or systemic clinical signs of infection, including death. Disease severity was measured using the following arbitrary scores: 0, 1, 2, 22284362 3 and 4. Each titration experiment was repeated 3 times. BALB/c mice died at the dose of 26106 pfu/mouse, whereas C57BL/6 mice succumbed at the dose of 26108 pfu/mouse. Accordingly, these dosages were used as lethal doses for challenging mice immunized with HSV1-LacZ Vaccination against Herpes Simplex Virus or HSV1-Tat. Similar titration experiments were performed in BALB/c mice in order to determine infectivity and attenuation of the HSV1-Tat and HSV1-LacZ vectors, at doses ranging from 104 to 108 pfu/mouse administered by the intravaginal route. Immunization with HSV1-Tat or HSV1-LacZ recombinants and challenge with wild-type 16041400 HSV1 To determine the dose of virus capable of inducing optimal antiHSV1 immune responses, C57BL/6 and BALB/c female mice were treated intravaginally with 102 to 104 pfu/mouse of the recombinant replication-competent HSV1-Tat virus, or with the control virus HSV1-LacZ, as described in the previous paragraph. Mice were sacrificed 15 days later to evaluate antiHSV1 immune responses, as described below. None of the doses of either vector tested for the immunization studies induced the appearance of local signs of infection, but the lowest dose of HSV1-Tat and HSV1-LacZ capable of inducing detectable cellular immune responses in 100% of treated mice was 103 pfu/mouse, which was therefore chosen as the optimal immunization dose. In immunization experiments, six-week-old C57BL/6 and BALB/c female were then treated intravaginally with 103 pfu/ mouse of HSV1-Tat or with HSV1-LacZ. Each experimental group was composed of 15 animals. Seven days post-infection, mice were sacrificed to evaluate any HSV1-specific T-cell responses on splenocyte cultures by means of IFN-c and IL-4 ELISpot assays. In 5 mice per experimental group, the presence of HSV1-specific antibodies was assessed at day 20 post-treatment by enzyme-linked immunoassays. At day 28, mice were challenged intravaginally with a lethal dose of wildtype HSV1 strain LV . After challenge, mice were observ
