Antibodies Are Required for Complete Vaccine-Induced Protection against Herpes Simplex Virus 2

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Herpes simplex virus 2 (HSV-2) 0ΔNLS is an attenuated live vaccine strain.
• This vaccine confers resistance to high-dose HSV-2 challenge, reducing viral spread, shedding, disease, and mortality.

Purpose of the Study:

• To investigate the specific requirements for HSV-2 0ΔNLS vaccine-induced protection.
• To elucidate the roles of viral replication, B cells, and antibodies in vaccine efficacy.

Main Methods:

• Compared protection from live vs. UV-inactivated HSV-2 0ΔNLS vaccine.
• Utilized B-cell-deficient μMT mice to assess the role of B cells.
• Administered passive HSV-2 antiserum to vaccinated μMT mice.

Main Results:

• Self-limited replication of HSV-2 0ΔNLS is necessary for protection against vaginal or ocular HSV-2 challenge.
• B-cell-deficient mice vaccinated with HSV-2 0ΔNLS showed significantly increased viral shedding and mortality post-challenge compared to wild-type mice.
• Passive antibody transfer restored vaccine-induced protection in B-cell-deficient mice.

Conclusions:

• Complete vaccine-induced protection against HSV-2 necessitates the presence of B cells.
• Virus-specific antibodies are the primary mediators of early protection conferred by the HSV-2 0ΔNLS vaccine.