Albert To, MS, PhD

Nominated From: University of Hawai’i

Research Site: Chulalongkorn University

Research Area: Vaccine Immunology

Primary Mentors: Dr. Vivek Nerurkar, Dr. Thiravat Hemachudha

Research Project

Characterization of the Long-Term Immunological Memory Responses Generated by Pre- and Post-Exposure Prophylaxis Rabies Virus Vaccination Regimens

Human rabies infections are considered a transboundary disease and result primarily from the bite of an infected canine or bat. Once symptoms develop, a case fatality rate of almost 100% is universal without immediate treatment. Worldwide it is estimated that upwards of 60,000 human deaths occur annually, primarily in Africa and Asia. Immunoprophylaxis can either be administered before or after rabies virus exposure in the form of pre-exposure (PrEP) or post-exposure (PEP) therapies. Treatment for a potentially rabid animal wound is PEP, however the prescribed treatment differs depending on whether a person has received PrEP. PEP is more aggressive for those with no previous rabies vaccination. For severe animal wounds or bat-related injury, rabies immunoglobin (RIG) must also be administered. While the longevity of the memory response generated by these therapies is well-document, the specific immunological pathway has not been thoroughly characterized. This study will examine the cellular mechanism of antibody longevity and memory T cell responses in individuals who have received either PrEP or PEP using modern flow cytometric techniques. We will furthermore examine if the administration of RIG influences the formation of long-term memory responses.

Research Significance

The results generated from this study will provide insight into the long-term immunological response of RABV PEP, with or without RIG, and PrEP in human subjects. This study will impact the course of recommended prophylaxis by providing a greater understanding of RABV immunity and possibly generate a plausible recommendation to provide PrEP in rabies-endemic regions rather than a costly regimen of full PEP and RIG. Additionally, this study will also determine if a single booster is sufficient to stimulate an anamnestic response, thus saving precious vaccine doses.


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