Identification and isolation of measles virus-specific neutralizing human monoclonal antibodies
Measles virus (MV) is a highly transmissible human virus, and is one of the leading causes of vaccine-preventable deaths, contributing to 146,000 deaths per year globally. Despite the existence of highly effective vaccines, there is need for the development of post-exposure therapeutics for use during measles outbreaks that often occur due to non-compliance with vaccination recommendations. Our laboratory focuses on identification of antibody-based therapeutics using monoclonal antibodies (mAb) derived from human B cells in immune donor blood. We are developing tools that allow for rapid screening of donor samples for measles-specific neutralizing antibodies with therapeutic potential. In this study, we used the MV-Edmonston vaccine strain of virus to identify MV-specific neutralizing antibodies. Using immuno-colorimetric assays to detect virus, we determined the optimal time to harvest MV from Vero cell monolayer cultures. After characterizing viral replication kinetics, we tested donor serum samples for the presence of MV-neutralizing antibodies by ELISA and focus reduction neutralization tests (FRNT). To isolate these antibodies, we harvested peripheral blood mononuclear cells (PBMC) from the same donor blood samples and stimulated the antibody-producing B cell population with MV. These cells then were fused to myeloma cells using electrical cytofusion to create hybridomas, which produce high concentrations of the monoclonal antibody. The target antibody was purified from culture supernatants. In this study, we present the preliminary steps in the isolation of strongly neutralizing human antibodies from donor samples, which will contribute to the development of a post-exposure prophylaxis for non-immune individuals who are exposed to measles virus.