to recover in a quarantine facility, where data on them was recorded. They had to be in perfect medical condition for the immunization, and the quarantine facility ensured that they were free of microbes which could infect the other horses. In the Behring facilities, the horses were viewed as life savers; therefore, they were well treated. A few of the individual horses used for serum production were named, and celebrated for their service to medicine, both human and non-human. At the end of the 19th century, every second child in Germany was infected with diphtheria, the most frequent cause of death in children up to 15 years. In 1891 Emil Behring saved the life of a young girl with diphtheria by injecting antiserum for the first time in history. Serum horses proved to be saviors of diphtheria-infected people. Subsequently, treatment of tetanus, rabies, and snake venom developed, and proactive protective vaccination against diphtheria and other microbial diseases began. In 1901, Behring won the first Nobel Prize in Medicine for his work in the study of diphtheria. Serum therapy became increasingly prevalent for infectious diseases, and was even used to treat patients during the influenza pandemic in 1918. Its uses were then quickly expanded to also treat diseases such as polio, measles, pneumococcus, Haemophilus influenza B, and meningococcus. In the 1920s, Michael Heidelberger and Oswald Avery proved that antibodies were proteins that targeted the capsule of the virus or bacteria. The discovery of antibiotics in the 1940s diminished interest in treating bacterial infections with antiserum, but its use for viral infections continued with the development of ethanol fractionation of blood plasma (which allowed for purified antibodies), discovered by Edwin Cohn. Antisera were developed to prevent and/or treat diphtheria, tetanus, Hepatitis B, rabies, varicella zoster virus, cytomegalovirus, and botulinum. However, these were not widely used. In 1984, Milstein and Köhler won a Nobel Prize for their paper that described their method for making murine monoclonal antibodies by immortalizing B cells as hybridomas. Another breakthrough occurred in 2003. A new technology allowed for heavy and light chain immunoglobulin genes to be amplified from human B cells and cloned into expression vectors. In 2008, this method was refined with a greater ability to sort cells and clone, which led to the discovery of more human monoclonal antibodies. In 1996, the FDA approved the use of RSV-IGIV (Respigam), a polyclonal antibody drug to inhibit respiratory