Combinatorial Herpes Simplex Vaccine Strategies: From Bedside to Bench and Back

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Herpes simplex virus (HSV) infections pose a significant global health challenge, necessitating effective vaccine development.
• Understanding the differential immune responses in asymptomatic versus symptomatic HSV-infected individuals is key to designing new vaccine strategies.
• Existing vaccine approaches require enhancement for improved efficacy and longevity.

Purpose of the Study:

• To review the status of ocular herpes vaccines in clinical trials.
• To discuss scientific advances in understanding HSV-specific immune responses.
• To present a novel combinatorial vaccine strategy targeting HSV, leveraging insights from naturally protected asymptomatic individuals.

Main Methods:

• Analysis of clinical trial data for ocular herpes vaccines.
• Examination of recent research on differential immune responses to HSV.
• Evaluation of a prime/pull vaccine approach combined with immune checkpoint blockade (PD-1, LAG-3, TIGIT, TIM-3).

Main Results:

• Distinct HSV-specific memory CD8+ T cell subsets are observed in asymptomatic and symptomatic individuals.
• A prime/pull vaccine strategy, which primes antiviral T cells systemically and attracts them to infection sites, shows enhanced protection.
• Combining the prime/pull approach with immune checkpoint blockade restores CD8+ T cell function and improves vaccine efficacy and longevity.

Conclusions:

• A combinatorial vaccine strategy using asymptomatic epitopes and immune checkpoint blockade shows promise for a successful HSV vaccine.
• The prime/pull approach, by targeting T cell migration and function, offers a novel pathway for herpes vaccine development.
• Further research into immune mechanisms of asymptomatic individuals can inform the design of next-generation HSV vaccines.