Expansion of the HSV-2-specific T cell repertoire in skin after immunotherapeutic HSV-2 vaccine.

The skin at the site of HSV-2 reactivation is enriched for HSV-2-specific T cells. To evaluate whether an immunotherapeutic vaccine could elicit skin-based memory T cells, we studied skin biopsies and HSV-2-reactive CD4+ T cells from peripheral blood mononuclear cells (PBMCs) by T cell receptor ß (TRB) sequencing before and after vaccination with a replication-incompetent whole virus HSV-2 vaccine candidate (HSV529). The representation of HSV-2-reactive CD4+ TRB sequences from PBMCs in the skin TRB repertoire increased after the first vaccine dose. We found sustained expansion after vaccination of unique, skin-based T-cell clonotypes that were not detected in HSV-2-reactive CD4+ T cells isolated from PBMCs. In one participant a switch in immunodominance occurred with the emergence of a T cell receptor (TCR) αß pair after vaccination that was not detected in blood. This TCRαß was shown to be HSV-2-reactive by expression of a synthetic TCR in a Jurkat-based NR4A1 reporter system. The skin in areas of HSV-2 reactivation possesses an oligoclonal TRB repertoire that is distinct from the circulation. Defining the influence of therapeutic vaccination on the HSV-2-specific TRB repertoire requires tissue-based evaluation.

Viral Shedding 1 Year Following First-Episode Genital HSV-1 Infection.

Importance: Herpes simplex virus type 1 (HSV-1) is the leading cause of first-episode genital herpes in many countries. Objective: To inform counseling messages regarding genital HSV-1 transmission, oral and genital viral shedding patterns among persons with first-episode genital HSV-1 infection were assessed. The trajectory of the development of HSV-specific antibody and T-cell responses was also characterized. Design, Setting, and Participants: Prospective cohort followed up for up to 2 years, with 82 participants followed up between 2013 and 2018. Participants were recruited from sexual health and primary care clinics in Seattle, Washington. Persons with laboratory-documented first-episode genital HSV-1 infection, without HIV infection or current pregnancy, were referred for enrollment. Exposures: First-episode genital HSV-1 infection. Main Outcomes and Measures: Genital and oral HSV-1 shedding and lesion rates at 2 months, 11 months, and up to 2 years after initial genital HSV-1 infection. Participants self-collected oral and genital swabs for HSV polymerase chain reaction testing for 30 days at 2 and 11 months and up to 2 years after diagnosis of genital HSV-1. Blood samples were collected at serial time points to assess immune responses to HSV-1. Primary HSV-1 infection was defined as absent HSV antibody at baseline or evolving antibody profile using the University of Washington HSV Western Blot. HSV-specific T-cell responses were detected using interferon γ enzyme-linked immunospot. Results: Among the 82 participants, the median (range) age was 26 (16-64) years, 54 (65.9%) were women, and 42 (51.2%) had primary HSV-1 infection. At 2 months, HSV-1 was detected from the genital tract in 53 participants (64.6%) and in the mouth in 24 participants (29.3%). Genital HSV-1 shedding was detected on 275 of 2264 days (12.1%) at 2 months and declined significantly to 122 of 1719 days (7.1%) at 11 months (model-predicted rate, 6.2% [95% CI, 4.3%-8.9%] at 2 months vs 3.2% [95% CI, 1.8%-5.7%] at 11 months; relative risk, 0.52 [95% CI, 0.29-0.93]). Genital lesions were rare, reported on 65 of 2497 days (2.6%) at 2 months and 72 of 1872 days (3.8%) at 11 months. Oral HSV-1 shedding was detected on 88 of 2247 days (3.9%) at 2 months. Persons with primary HSV-1 infection had a higher risk of genital shedding compared with those with nonprimary infection (model-predicted rate, 7.9% [95% CI, 5.4%-11.7%] vs 2.9% [95% CI, 1.7%-5.0%]; relative risk, 2.75 [95% CI, 1.40-5.44]). Polyfunctional HSV-specific CD4+ and CD8+ T-cell responses were maintained during the follow-up period. Conclusions and Relevance: Genital HSV-1 shedding was frequent after first-episode genital HSV-1, particularly among those with primary infection, and declined rapidly during the first year after infection.

Prevalent and Diverse Intratumoral Oncoprotein-Specific CD8+ T Cells within Polyomavirus-Driven Merkel Cell Carcinomas.

Merkel cell carcinoma (MCC) is often caused by persistent expression of Merkel cell polyomavirus (MCPyV) T-antigen (T-Ag). These non-self proteins comprise about 400 amino acids (AA). Clinical responses to immune checkpoint inhibitors, seen in about half of patients, may relate to T-Ag-specific T cells. Strategies to increase CD8+ T-cell number, breadth, or function could augment checkpoint inhibition, but vaccines to augment immunity must avoid delivery of oncogenic T-antigen domains. We probed MCC tumor-infiltrating lymphocytes (TIL) with an artificial antigen-presenting cell (aAPC) system and confirmed T-Ag recognition with synthetic peptides, HLA-peptide tetramers, and dendritic cells (DC). TILs from 9 of 12 (75%) subjects contained CD8+ T cells recognizing 1-8 MCPyV epitopes per person. Analysis of 16 MCPyV CD8+ TIL epitopes and prior TIL data indicated that 97% of patients with MCPyV+ MCC had HLA alleles with the genetic potential that restrict CD8+ T-cell responses to MCPyV T-Ag. The LT AA 70-110 region was epitope rich, whereas the oncogenic domains of T-Ag were not commonly recognized. Specific recognition of T-Ag-expressing DCs was documented. Recovery of MCPyV oncoprotein-specific CD8+ TILs from most tumors indicated that antigen indifference was unlikely to be a major cause of checkpoint inhibition failure. The myriad of epitopes restricted by diverse HLA alleles indicates that vaccination can be a rational component of immunotherapy if tumor immune suppression can be overcome, and the oncogenic regions of T-Ag can be modified without impacting immunogenicity.

Genome-Wide Surveillance of Genital Herpes Simplex Virus Type 1 From Multiple Anatomic Sites Over Time.

Here we present genomic and in vitro analyses of temporally separated episodes of herpes simplex virus type 1 (HSV-1) shedding by an HSV-1-seropositive and human immunodeficiency virus (HIV)/HSV-2-seronegative individual who has frequent recurrences of genital HSV-1. Using oligonucleotide enrichment, we compared viral genomes from uncultured swab specimens collected on different days and from distinct genital sites. We found that viral genomes from 7 swab specimens and 3 cultured specimens collected over a 4-month period from the same individual were 98.5% identical. We observed a >2-fold difference in the number of minority variants between swab specimens from lesions, swab specimens from nonlesion sites, and cultured specimens. This virus appeared distinct in its phylogenetic relationship to other strains, and it contained novel coding variations in 21 viral proteins. This included a truncation in the UL11 tegument protein, which is involved in viral egress and spread. Normal immune responses were identified, suggesting that unique viral genomic features may contribute to the recurrent genital infection that this participant experiences.

T-cell Responses to HSV-1 in Persons Who Have Survived Childhood Herpes Simplex Encephalitis.

BACKGROUND: Herpes simplex encephalitis (HSE) after primary herpes simplex virus (HSV)-1 infection can occur in children due to inborn errors of cell-intrinsic immunity in the central nervous system. Paradoxically, symptomatic mucocutaneous HSV-1 recurrences are rare survivors of childhood HSE. T-cell-acquired immunity is thought to be involved in control of recurrent mucocutaneous HSV infection. We thus tested HSV-1-specific immunity in HSE survivors. METHODS: We obtained serum and peripheral blood mononuclear cells (PBMCs) from participants a median of 13.5 years after HSE. HSV-1 and HSV-2 IgG was detected by type-specific immunoblot. PBMCs from subjects passing quality control criteria were tested using enzyme-linked immunospot assay for CD4 interferon-γ responses with an HSV-1 lysate and for CD8 responses using pooled synthetic HSV-1 peptide CD8 T-cell epitopes. Healthy adult PBMCs were used to standardize assays and as comparators. RESULTS: All participants were HSV-1 seropositive. Most (23/24) HSE survivors had human leukocyte antigen class I types matching the human leukocyte antigen restriction of the pooled peptides. We detected HSV-specific CD8 T-cell responses in 14 of 24 (58%) HSE survivors and in 9 of 9 healthy HSV-1 seropositive adults. HSV-specific CD4 T-cell responses were present in all 5 HSE subjects tested and in 8 of 9 healthy adults. Response magnitudes were overlapping between subject groups. CONCLUSIONS: The defects in cell-intrinsic immunity leading to failure to control primary central nervous system HSV-1 infection do not preclude the acquisition of specific immunity or the control of recurrent mucocutaneous HSV infections. The rarity and lack of severe or recurrent mucocutaneous HSV infection in survivors of childhood HSE corresponds with intact adaptive T-cell immunity.