Differences in the Recognition of CTL Epitopes during Primary and Secondary Responses to Herpes Simplex Virus Infection in Vivo

The immune response to HSV infection in C57BL/6 mice includes a CTL population that recognizes the virion envelope glycoprotein gB. However, previous studies showed that CTL specific for other vital determinants were also responding to HSV infection. These studies demonstrate that an additional determinant is the HSV immediate-early protein ICP27. During the primary response, both gB- and ICP27-specific CTL were detected in the draining lymph node. In response to reinfection, ICP27-specific CTL were present early in the lymph node, while the appearance of gB-specific CTL activity was delayed. Analysis of the primary amino acid sequence of ICP27 predicted two potential Kb-binding epitopes, one of which sensitized uninfected cells for lysis by HSV-specific CTL. In addition, ICP27 epitope-specific CTL activity was detected in the splenic memory CTL pool. These results show that CTL which recognize different antigens may also exhibit differences in how they respond to HSV reinfection in vivo.