Jonathan Lai studies the use of monoclonal antibodies (mAbs), or cocktails thereof, for treatment of viral diseases. His laboratory uses state-of-the-art protein engineering technologies to develop novel immunotherapeutics against several viruses. A recent example is the use of “synthetic antibody technology” to develop the first humanized protective mAbs against the Sudan ebolavirus species, the result of a large multi-institution collaborative effort. Synthetic antibody technology is a phage-based approach that allows the production and screening of very large (> 1010) protein libraries. There are five species of ebolavirus and, while many potential mAbs are available for the Zaire ebolavirus species, few are available for Sudan ebolavirus despite its high pathogenicity and increasing prevalence. Subsequent efforts are focused on using nascent protein engineering technologies to address unmet immunotherapeutic needs for this and other viruses.