Persistence of mucosal T cell responses to herpes simplex virus type 2 (HSV-2) in the female genital tract

Relatively little is known about the human T cell response to HSV-2 in the female genital tract, a major site of heterosexual HSV-2 acquisition, transmission and reactivation. In order to understand the role of local mucosal immunity in HSV-2 infection, T cell lines were expanded from serial cervical cytobrush samples from 30 HSV-2 infected women and examined for reactivity to HSV-2. Approximately 3% of the CD3+ T cells isolated from the cervix were HSV-2 specific and of these, a median of 91.3% were CD4+ while a median of 3.9% were CD8+. HSV-2 specific CD4+ T cells expanded from the cervix were not only more frequent than CD8+ T cells but also exhibited greater breadth in terms of antigenic reactivity. T cells directed at the same HSV-2 protein were often detected in serial cervical cytobrush samples and in blood. Thus, broad and persistent mucosal T cell responses to HSV-2 were detected in the female genital tract of HSV-2+ women suggesting that these cells are resident at the site of HSV-2 infection. Understanding the role of these T cells at this biologically relevant site will be central to the elucidation of adaptive immune mechanisms involved in controlling HSV-2 disease.