Virologic and Immunologic Evidence of Multifocal Genital Herpes Simplex Virus 2 Infection

Abstract

Genital herpes simplex virus (HSV) reactivation is thought to be anatomically and temporally localized, coincident with limited ganglionic infection. Short, subclinical shedding episodes are the most common form of HSV-2 reactivation, with host clearance mechanisms leading to rapid containment. The anatomic distribution of shedding episodes has not been characterized. To precisely define patterns of anatomic reactivation, we divided the genital tract into a 22-region grid and obtained daily swabs for 20 days from each region in 28 immunocompetent, HSV-2-seropositive persons. HSV was detected via PCR, and sites of asymptomatic HSV shedding were subjected to a biopsy procedure within 24 h. CD4؉ and CD8 ؉ T cells were quantified by immunofluorescence, and HSV-specific CD4 ؉ T cells were identified by intracellular cytokine cytometry. HSV was detected in 868 (7%) of 11,603 genital swabs at a median of 12 sites per person (range, 0 to 22). Bilateral HSV detection occurred on 83 (67%) days with shedding, and the median quantity of virus detected/day was associated with the number of sites positive (P < 0.001). In biopsy specimens of asymptomatic shedding sites, we found increased numbers of CD8 ؉ T cells compared to control tissue (27 versus 13 cells/mm 2 , P ‫؍‬ 0.03) and identified HSV-specific CD4 ؉ T cells. HSV reactivations emanate from widely separated anatomic regions of the genital tract and are associated with a localized cellular infiltrate that was demonstrated to be HSV specific in 3 cases. These data provide evidence that asymptomatic HSV-2 shedding contributes to chronic inflammation throughout the genital tract. IMPORTANCEThis detailed report of the anatomic patterns of genital HSV-2 shedding demonstrates that HSV-2 reactivation can be detected at multiple bilateral sites in the genital tract, suggesting that HSV establishes latency throughout the sacral ganglia. In addition, genital biopsy specimens from sites of asymptomatic HSV shedding have increased numbers of CD8 ؉ T cells compared to control tissue, and HSV-specific CD4 ؉ T cells are found at sites of asymptomatic shedding. These findings suggest that widespread asymptomatic genital HSV-2 shedding is associated with a targeted host immune response and contributes to chronic inflammation throughout the genital tract. H erpes simplex virus 2 (HSV-2) infects over 500 million people worldwide (1) and is the leading cause of genital ulcer disease (2) and increases the risk of HIV acquisition (3). Herpetic genital ulcers in the immunocompetent person are localized with respect to time and anatomic site (4), consistent with reactivation of virus from the ganglion innervating this region. However, most HSV genital shedding is subclinical, with rapid onset and clearance (5, 6). Such subclinical reactivation may be more widespread in the genital area (7), consistent with frequent leakage of virus into the genital skin and mucosa with localized host containment (8, 9). Mathematical models suggest that observed shedding patterns are the result of ove...

Extensive CD4 and CD8 T Cell Cross-Reactivity between Alphaherpesviruses

“…Responder cells are prepared by enriching and expanding memory virus-specific polyclonal T-cell lines that contain multiple epitope-specific populations. Herein, we extend previous virus-specific reports in which we discovered many viral T-cell antigens and epitopes (16, 24-26) to delineate and measure T-cell cross-reactivity across the Alphaherpesvinae subfamily.…”

“…HSV-1 17+ and HSV-2 186 antigens and mock Vero (for HSV) and HET antigens were similarly prepared (32). HSV-1, HSV-2, and VZV ORFeome-covering proteins are described (16, 24, 26). For CD4 epitope mapping, regions of VZV ORF24 and ORF68 were cloned into pDEST203 (25) (primers available on request).…”

Genetic diversity of equine herpesvirus 1 isolated from neurological, abortigenic and respiratory disease outbreaks

“…The amount of subclinical reactivation from these sites and the mechanisms of subsequent clearance are unknown. The anatomically distinct nature of these sites of latency raises the possibility that viruses at different sites may reactivate independently, and that the overall population may have been derived from viruses originating from separate shedding episodes, similar to that reported for herpes simplex virus 2 (HSV‐2) (Johnston et al., 2014). In the present study, strains Essex/199/05 and Essex/200/05 were isolated from different tissues from an individual abortion and had identical sequences, as expected (Figure 2a, clade 7).…”

The challenges and opportunities for the development of a T-cell epitope-based herpes simplex vaccine

“…passage of virus from mother to newborn) is highest among women who have newly acquired HSV-2 in the genital tract (i.e. women naturally infected during the third trimester of pregnancy) and who were otherwise seronegative [25, 26]. This risk of transmission is increased 300 fold if vaginal shedding occurs at the time of delivery [27].…”

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