FIG 6.

Correlates of protection with function and exhaustion of local vaginal mucosa-resident CD8⁺ T cells following RR2 protein therapeutic vaccination of HSV-2-infected guinea pigs. (A) Timeline of HSV-2 infection, IVAG and intramuscular (IM) immunization, and immunological and virological analyses. Once acute infection was resolved, latently infected animals were randomly divided into three groups (n = 11) and then vaccinated twice intramuscularly, on days 15 and 25 postinfection, with either RR2 protein emulsified in alum plus CpG adjuvants (group 1) or the replication-defective dl5-29 vaccine (positive control; group 2). Mock-vaccinated guinea pigs, which received adjuvant alone, were used as a negative control (group 3). (B) Cumulative virus shedding detected RR2-vaccinated, dl5-29-vaccinated and mock-vaccinated controls is shown. (C) Cumulative vaginal lesions (left) and cumulative number of days with recurrent genital lesions (right) detected for RR2-vaccinated, dl5-29-vaccinated, and mock-vaccinated controls are shown. (D) Representative images of genital lesions in guinea pigs vaccinated with RR2 protein or dl5-29 vaccine and mock-vaccinated animals. (E) Frequencies of CD4⁺ and CD8⁺ T cells detected by FACS in the VM tissue of RR2-vaccinated animals. (F) Frequencies of functional CRTAM⁺ CD8⁺ T cells (top row of plots and graphs) and of CFSE⁺ CD8⁺ T cells (bottom row of plots and graphs) and IFN-γ-producing cells, enumerated ex vivo by ELISpot assay (bottom portion) in the VM of RR2-vaccinated and dl5-29-vaccinated animals compared to those in mock-vaccinated animals. (G) Frequencies of exhausted PD-1⁺ CD8⁺ T cells (top row of plots and graphs) and TIM-3⁺ CD8⁺ T cells (bottom row of plots and graphs) detected in the VM of RR2-vaccinated and dl5-29-vaccinated animals compared to those in mock-vaccinated animals. The indicated P values show statistical significance between RR2-vaccinated and mock-vaccinated control groups. *, P < 0.05 (considered significant).