Antibodies are a relatively new treatment class that has shown great promise for the treatment of autoimmunity, cancer, and viral infections. Antibodies can be discovered either in-vivo or in-vitro. While in-vivo discovery is the predominant approach, it relies on animal models with a humanized immune system, which exhibit two key shortcomings. First, use of animal models can pose ethical concerns. Second, certain human antigens may not cause immune reactions in humanized animals.