Beatrice Hahn

Beatrice H. Hahn is an American virologist and biomedical researcher known for discovering the origins of the human immunodeficiency virus (HIV).

Beatrice Hahn was born in Munich, Germany on February 13, 1955. Her zest for medicine began at an early age, as she was greatly influenced by her father who was a distinguished primary care physician. Her father started practicing medicine in rural Bavaria, where he was one of the first physicians in the area to utilize an X-ray machine for the purpose of diagnostics. His passion and dedication to his career greatly inspired Beatrice, and she set her sights on becoming a physician as soon as she began her education.

Hahn left home to attend Technical University Munich, Munich, Germany, where she gained her M.D. degree in 1981. She worked as an intern at Ludwig Maximilians University of Munich from 1981–1982. She attained her Doctorate in Medicine from Technical University Munich in 1982. Her doctoral thesis had influences from her upbringing and early childhood. Hahn enjoyed to reminisce on her memories of herding and milking cows as a child. She began to reflect on how integral a role cattle played in her father's old place of residence in rural Bavaria. Hahn began to ponder if the close relationship of people and cattle could be detrimental to the humans, due to the bovine virus, a very serious economic disease of cattle. Her thesis specifically focused on the bovine leukemia virus, which is closely related to the human tumor virus HTLV-1.

After graduating, Hahn began her career with a fellowship in Robert Gallo's National Cancer Institute laboratory, then joined the faculty and established her own laboratory at the University of Alabama at Birmingham (UAB). Hahn met Robert Gallo when she was a student at the Technical University of Munich. He was a virologist and a researcher at the National Cancer Institute in Bethesda, Maryland. Most of his research was focused on leukemia, the disease that had taken his sister's life at an early age. One of the main areas of interest for Gallo was tumor-causing retroviruses. This sparked the interest of Hahn because Bovine leukemia virus is an example of such a retrovirus. Hahn's wish to work in Gallo's lab was made possible when she received a fellowship from the German Science Foundation. She left her home in Germany and started research at the National Cancer Institute on May 1, 1982. There, she began her research into the origins of HIV/AIDS. AIDS had just become prevalent in the United States a year before she arrived. All of the patients with the reported disease were gay males and displayed symptoms of a skin cancer and unique form of pneumonia. Gallo's laboratory had been studying this new disease outbreak and Hahn joined in on the investigation. In 1983, a man named George Shaw joined Gallo's laboratory and he and Hahn immediately began to collaborate on their research together. After a fellow researcher, Mikulas Popovic, successfully cultured and isolated the virus, Hahn and Shaw cloned the virus's genome. They were able to determine that the isolated retrovirus was the cause of AIDS. They went on to discover that HIV originated from chimpanzees, gorillas, and sooty mangabey strains of simian immunodeficiency virus (SIV). Contrary to the prevailing scientific opinion, Hahn found that SIV does cause disease in its hosts and that chimpanzees represent a reservoir of HIV. She has also cloned HIV-2 and catalogued genetic variants of HIV-1 and their drug resistance.

Hahn and Shaw had many papers published and in 1985 they were recruited by the University of Alabama at Birmingham's Comprehensive Cancer Center to lead and conduct human retrovirus research. Both excelled in their work and Hahn went on to become a distinguished professor in the Departments of Microbiology and medicine as well as work as co director at the Center for AIDS research. Hahn and her research partner George Shaw then married in 1988.

After working at UAB, Hahn moved to the Center for AIDS Research at the University of Pennsylvania, where she has used non-invasive fecal sampling to investigate SIV and HIV in primate populations. Her research has also included the origins of the human malaria parasite, Plasmodium falciparum; determining that P. falciparum was transmitted to humans from gorillas in a single event.

Hahn conducted her research from an evolutionary perspective when studying disease mechanisms and HIV/SIV gene function. Simian immunodeficiency viruses (SIVs) are a type of retroviruses that are capable of inefcting a myriad of non-human primate species located in Africa. Hanh made the startling discovery that certain SIVs had traversed between humans and certain nonhuman primate species a multitude of times to result in types 1 and 2 human immunodeficiency virus (HIV). The two viruses she identified were SIVcpz from chimpanzees (Pan troglodytes) and SIVsmm from sooty mangabeys (Cercocebus atys). The realization that the transfer of SIVs had generated HIV led Hahn to conclude that presence of Acquired Immunodeficiency Syndrome (AIDS) was due to the cross-species infections of humans by lentiviruses of primate origin. A careful analysis of the high degree of relatedness between chimpanzees and humans was a major focus point in Hanh’s laboratory. Knowing that chimpanzees and humans share more than 98% sequence identity across their genomes, Hanh sought to uncover what exactly varies in the interactions between virus and host that cause differences in viral pathogenicity. Hahn made advances in the understanding the origin of HIV-1, SIVcpz, and natural SIVcpz reservoirs.

Study on Origin of HIV-1

The theorization that chimpanzees may be source of HIV-1 began when a chimpanzee was found to have a lentivirus (SIVcpzGAB1) that was closely related to HIV-1. The genome of SIVcpzGAB1 had an accessory gene that was so far unique to HIV-1 as well as many of the same reading frames. However, experiments carried out on more chimpanzees continuously resulted in apparently contradictory results as to whether chimpanzees were the original source of the SIVcpz. One experiment performed on fifty chimpanzees resulted in only two possessing HIV-1 cross-reactive antibodies, which showed a much lower SIVcpz infection rate in contrast to other naturally occurring SIV infections. This finding indicated that there was a third unknown source that both humans and chimpanzees could have acquired the virus from. Another study reported that a chimpanzee named Noah had a virus called SIVcpzANT that clustered with SIVcpzGAB1 (and HIV-1 strains) in phylogenetic trees but was twice as distant from SIVcpzGAB1 and HIV-1 strains as they were from each other, which resulted in more support for the a third unknown source being the true SIVcpz reservoir.

Hahn was able to prove the original theory through analyzation of the SIVcpz phylogeny in relation to the subspecies origin of the infected chimpanzee host. Her studies showed that the chimpanzees that had viruses similar to HIV-1 and to one another belonged to the same group; P.t. troglodytes. On the other hand, Noah, the chimpanzee with the virus that was extremely distant, was a P.t. schweinfurthii. This proved that the origin of a subspecies' chimpanzee host was what was responsible for two different phylogenetic lineages of SIVcpz strains. Hahn's careful phylogenetic analysis also supported that the source of HIV-1 was the chimpanzees that were members of P.t. troglodytes.

• Fellow, National Academy of Medicine (2012)
• Fellow, American Academy of Microbiology
• Junior Faculty Development Award at University of Alabama at Birmingham
• Recipient, Birmingham Business Journal Top Birmingham Women, 1999
• Recipient, The Max Cooper Award for Research Excellence, 2001
• Recipient, The 50 Most Important Women in Science, Discover Magazine, 2002
• Elected, US National Academy of Sciences, 2012

• Sharp, Paul M.; Hahn, Beatrice H. (2011-09-01). "Origins of HIV and the AIDS Pandemic". Cold Spring Harbor Perspectives in Medicine. 1 (1). doi:10.1101/cshperspect.a006841. ISSN 2157-1422. PMC 3234451. PMID 22229120. 
• Parrish, Nicholas F.; Gao, Feng; Li, Hui; Giorgi, Elena E.; Barbian, Hannah J.; Parrish, Erica H.; Zajic, Lara; Iyer, Shilpa S.; Decker, Julie M. (2013-04-23). "Phenotypic properties of transmitted founder HIV-1". Proceedings of the National Academy of Sciences. 110 (17): 6626–6633. doi:10.1073/pnas.1304288110. ISSN 0027-8424. PMC 3637789. PMID 23542380.