Vaccines and me

I started my scientific career thinking I wanted to be an ecologist. I did some field work where I was an undergraduate at Miami University in Ohio but it became clear I wasn’t particularly suited for that type of research. I received a Ph.D. in Biology at the University of Notre Dame working on physiological adaptations to cold, isolating a thermal hysteresis protein (antifreeze protein) from Tenebrio molitor, the meal worm.¹ I then went on to hone my skills as a biochemist at the University of Wisconsin, Department of Biochemistry, but soon got the opportunity to move to the Microbiology Department at the University of Geneva, Switzerland. It was 1981 and molecular biology had suddenly come of age with the ability to sequence DNA. It was an exciting time but also a very naïve time thinking that for instance the cloning of complicated enzymes, like the ones I had worked on at Wisconsin, was going to be simple and questions easily answered. I found myself in the laboratory of Daniel Kolokofsky. He was for all intent and purposes a molecular virologist. I knew little of microbiology much less of virology. After a period of time he asked me to consider working on a segmented RNA virus La Crosse Encephalitis Virus (LAC) (Bunyaviridae). His lab was mostly focused on mechanisms of transcription of VSV (Rhabdoviridae) and Sendai virus (Paramyxoviridae). His lab would complete the sequence of Sendai virus while I was there, a milestone at the time. I thought working on a different family of viruses and seeing how they compared to our understanding of their transcription and replication would be interesting. Coincidentally one summer, while I was a graduate student at Notre Dame, I had participated in a survey of mosquitoes in the South Bend, IN area because of an outbreak of LAC. At the time, it was simply to help subsidize my salary.

My work with LAC showed that unlike rhabdo and paramyxo viruses, LAC, a bunya virus, utilized a remarkably similar transcription and replication pattern to the recently described cap-snatching mechanism of initiating transcription of influenza viruses.² While flu viruses cap-snatched in the nucleus, bunyaviruses and subsequently arenaviruses all initiated transcription in the cytoplasm.³ It was an exciting time to be starting to work with viruses as the new molecular techniques allowed us to ascertain aspects of their molecular mechanisms much easier than previously. Although if one asks graduate students today what they think of the techniques we were using, I believe primitive might be a word that would be mentioned! In any case I was hooked as a virologist and remain hooked today.

After leaving Dan's lab I moved to Harvard Medical School and Boston's Children's Hospital. It was there that I really became a virologist interested in not just understanding their molecular mechanisms but pursuing ways to stop their infections. Boston's Children's Hospital, like all pediatric hospitals, has specific interests in diseases of infants such as Respiratory Syncytial virus (RSV). In the 1960s an RSV vaccine developed by NIH was used and had the unexpected consequence of causing more harm than any protection. The vaccine caused disease enhancement. This result was one of the first where vaccines which previously would be automatically considered safe, now had to be tested for the possibility that they might cause worsened disease. There was no good animal model to examine RSV pathogenesis and it remains that way today. The 1980s also saw the outbreak of HIV, including in infants. The first AIDS patient was seen at Boston's Children's Hospital sometime between 1983 and 1985. It left an indelible mark on those of us who were there and suddenly realized the extent of the outbreak and that it was nothing like we had ever seen or hopefully see ever again in our lifetime. The history of HIV vaccine development is well documented and has served as an example of how complicated a virus can be that infects the immune system. It became clear that in order to develop a vaccine we need first to understand the virus, the correlates of protection and how to manage such a complicated pathogen. Most of the work I did at Children's focused on anti-viral treatments such as ribavirin.⁴ I also became intrigued by single cell parasitic infections and how little was known of these organisms and their cellular functions. I started to wonder how viruses could play a role in understanding host-cell machinery.

Eventually my lab developed a hypothesis that testing the protozoan parasite Leishmania extracts for RNA-dependent RNA-polymerase activity would identify any single, double, segmented or non-segmented virus. We tested the hypothesis and identified a dsRNA virus now known as Leishmaniavirus.⁵ There are several strains of this virus and other single-cell organisms are now known to be infected with dsRNA viruses.

In 1996, I accepted the job of Chair of Virology and Immunology at Texas Biomedical Research Institute (Texas Biomed) previously known as Southwest Foundation for Biomedical Research. My new job was to rebuild a department of virology and immunology. It was a challenging time to be building a new department. Funding at the National Institute for Allergy and Infectious Diseases (NIAID) was hovering at less than 10% for R01 applications. However Texas Biomed offered some interesting and unique resources. It had a history of working with non-human primates (NHPs) (in 1999 it became a NIH National Primate Research Center) and it had a BSL4 glove box. The work being done at in the glove box was only Herpes B (Simian Herpes) Virus. It is a potentially lethal virus in humans but well tolerated in macaques. Recruitment proved quite a lot easier than one might expect since everyone who applied had a particular reason for coming to Texas Biomed, they either wanted to work on NHPs or were interested in high containment viruses. Within a few years we built a new lab which was a full suit BSL4 lab, the first new high containment lab in the USA in 20 years. The building consisted of 12 BSL2 labs, 3 BLS3 labs and a BSL4 lab. The BSL4 lab was designed to be primarily a diagnostic laboratory for Herpes B. We became active in the lab in March of 2000. It wasn't going to be particularly busy but things were about to change.

About Jean Patterson. Dr. Patterson received her PhD from University of Notre Dame, Indiana (1979), and postdoctoral training from University of Wisconsin (1979–81) and University of Geneva, Switzerland (1981–4). In 1984 she moved to Harvard Medical School, where she was Assistant Professor (1986–91) then Associate Professor (1991–6) of Microbiology and Molecular Genetics. Dr. Patterson moved to San Antonio, Texas, where she holds the positions of E.M. Stevens Chair for Biomedical Research and Adjunct Professor at the Department of Microbiology, The University of Texas Health Science Center at San Antonio (since 1996). Recently she became the Chair of Biosafety level-4 Task Force at the Department of Virology and Immunology, Texas Biomedical Research Institute. Dr. Patterson has co-authored >100 scientific articles and book chapters, mostly on the biology and development of vaccines for hemorrhagic fever viruses (Ebola, Marburg and Lassa viruses), the anthrax bacterium Bacillus anthracis and the protozoan parazite Leishmania. Her research thus requires the highest biosafety work conditions. Dr. Patterson has been a member of numerous biodefense and biosafety committees, including Northeast Biodefense Center External Evaluation Committee (2010–2), American Society for Microbiology Biodefense Program Committee (since 2008, Chair in 2012–4) and National Scientific Advisory Board for Biosecurity (since 2014). She was an Advisor to the US. Senate Weapons of Mass Destruction Commission (2009–11), and a member of the NIH Center of Biomedical Research Excellence (2000–2) and the NIH Blue Ribbon Panel (2008–12).

In October of 2001 after the 9/11 attacks of that year there was another attack. Anthrax was discovered to be in the mail system and 5 people would ultimately die in those attacks. The country felt it was at war and newly at war with bioterrorism. The US government put more money in that area than they had ever before even considered. Close to a billion dollars was to be spent developing countermeasures against what would be later described as the select agents. Select agents are those pathogens that the US government had determined to be potential biological weapons, weapons of bioterror. Those pathogens not only included the already used anthrax, but all of the hemorrhagic fever viruses (HFVs). All of the HFV which were classified as BSL4 agents were now in the Select Agent Program; those HFVs included Ebola, Marburg and Lassa fever. Within the next 2 years Texas Biomed and its BSL4 program became an ABSL4 program, primarily, for all 3 of these major HFVs. The countermeasures included drug therapies and vaccines. It has become my assertion for a number of years that without the anthrax attacks there would be no potential Ebola vaccines in clinical trials today.

Tropical diseases, which included HFVs, had always been seriously underfunded. They were exotic diseases. A lot of founding agencies of biomedical research, believed only existed and would exist in the developing worlds, of Africa, South America and South East Asia. There was no known profitable market for countermeasures to these diseases, particularly vaccines, which are notoriously expensive to develop and produce. The notion was, that only with a huge and wealthy domestic market, vaccines could be profitably developed. It was only the US and European markets that, for many decades, pharmaceutical companies considered developing vaccines. The US military had for some time been involved in countermeasure research to tropical diseases in large part because the US soldier has and could be deployed to areas where these diseases existed. One of the more productive programs developed by the US military was in the development of vaccines against Korean Hemorrhagic Fever virus with Renal Syndrome (HFRS). They had discovered it was a member of the Bunyaviridae family of viruses and they developed reagents to diagnose and treat HFRS. Ironically it was thought to exist only in SE Asia particularly in Korea and China.⁶ In 1994 there was an outbreak of a new respiratory syndrome in the 4 corners area of the US. Using diagnostic reagents developed at the United States Army Medical Research Institute of Infectious Diseases at Ft. Detrick MD (USAMRIID), CDC investigators determined that this pathogen was also a member of the Bunyaviridae family and later put it in the genus Hantavirus.⁷ Subsequently, Hantaviruses have been discovered worldwide. Now that the realization these pathogens could be found outside the developing world, funds were allocated to protect the US population from deliberate release of these organisms, or as was subsequently known, their natural emergence in the US itself.

Texas Biomed began to evaluate first Lassa fever vaccines. We looked first at a live attenuated vaccine, a Mopeia Lassa recombinant (ML29). It had the Lassa glycoprotein with the Mopeia smaller segment. This first vaccine ultimately was shown to provide sterilizing immunity in strain 13  guinea pigs.⁸. We realized that we needed to utilize NHPs in the laboratory and given the size of our lab we decided to determine if a smaller new world monkey, the common marmoset, could be used to evaluate HFV vaccines. We showed it to be a very powerful model for Lassa fever and ultimately our vaccine provided protection in the marmoset. It provided us with much information regarding correlates of protection during a Lassa infection.⁹ However given that it is a live vaccine, the chances of it being used in areas where Lassa fever is endemic, West Africa, is not likely. Current work suggests that while a live attenuated vaccine may be the best in providing protection, it is not safe enough to be used for worldwide, large scale immunization.

Ultimately, our attention turned to filoviruses. The US government was interested in developing a bivalent vaccine against both Ebola and Marburg virus. Our laboratory has been actively involved in the development of an Ebola vaccine since 2009. While the initial goal was a bivalent vaccine, however, when the outbreak of Ebola in West Africa began to unfold the US government moved to develop a singular vaccine against Ebola Zaire. At the same time we also showed that the marmoset can serve as an effective animal model for Ebola and Marburg virus.¹⁰ Currently, trials are on-going for at least 3 vaccines against Ebola virus. Texas Biomed and its ABSL4 was critical in testing and evaluating these vaccines. Whether any of them will be selected and ultimately stockpiled or used in Africa remains to be seen.

Vaccines present one of the greatest advances in improvement of human health of any form of technology available today. As we learn more and more about the immune system, how to challenge it and use it to our advantage, there is no limit to the amount of protection from infectious diseases they will ultimately provide to us.