Historical Advances in Structural and Molecular Biology and How They Impacted Vaccine Development.

Vaccines are among the greatest tools for prevention and control of disease. They have eliminated smallpox from the planet, decreased morbidity and mortality for major infectious diseases like polio, measles, mumps, and rubella, significantly blunted the impact of the COVID-19 pandemic, and prevented viral induced cancers such as cervical cancer caused by human papillomavirus. Recent technological advances, in genomics, structural biology, and human immunology have transformed vaccine development, enabling new technologies such as mRNA vaccines to greatly accelerate development of new and improved vaccines. In this review, we briefly highlight the history of vaccine development, and provide examples of where advances in genomics and structural biology, paved the way for development of vaccines for bacterial and viral diseases.

Modified Vaccinia Virus Ankara: History, Value in Basic Research, and Current Perspectives for Vaccine Development.

Safety tested Modified Vaccinia virus Ankara (MVA) is licensed as third-generation vaccine against smallpox and serves as a potent vector system for development of new candidate vaccines against infectious diseases and cancer. Historically, MVA was developed by serial tissue culture passage in primary chicken cells of vaccinia virus strain Ankara, and clinically used to avoid the undesirable side effects of conventional smallpox vaccination. Adapted to growth in avian cells MVA lost the ability to replicate in mammalian hosts and lacks many of the genes orthopoxviruses use to conquer their host (cell) environment. As a biologically well-characterized mutant virus, MVA facilitates fundamental research to elucidate the functions of poxvirus host-interaction factors. As extremely safe viral vectors MVA vaccines have been found immunogenic and protective in various preclinical infection models. Multiple recombinant MVA currently undergo clinical testing for vaccination against human immunodeficiency viruses, Mycobacterium tuberculosis or Plasmodium falciparum. The versatility of the MVA vector vaccine platform is readily demonstrated by the swift development of experimental vaccines for immunization against emerging infections such as the Middle East Respiratory Syndrome. Recent advances include promising results from the clinical testing of recombinant MVA-producing antigens of highly pathogenic avian influenza virus H5N1 or Ebola virus. This review summarizes our current knowledge about MVA as a unique strain of vaccinia virus, and discusses the prospects of exploiting this virus as research tool in poxvirus biology or as safe viral vector vaccine to challenge existing and future bottlenecks in vaccinology.

Lights and shades on an historical vaccine canine distemper virus, the Rockborn strain.

Both egg- and cell-adapted canine distemper virus (CDV) vaccines are suspected to retain residual virulence, especially if administered to immuno-suppressed animals, very young pups or to highly susceptible animal species. In the early 1980s, post-vaccine encephalitis was reported in dogs from various parts of Britain after administration of a particular batch of combined CDV Rockborn strain/canine adenovirus type-1 vaccine, although incrimination of the Rockborn strain was subsequently retracted. Notwithstanding, this, and other reports, led to the view that the Rockborn strain is less attenuated and less safe than other CDV vaccines, and the Rockborn strain was officially withdrawn from the markets in the mid 1990s. By sequencing the H gene of the strain Rockborn from the 46th laboratory passage, and a commercial vaccine (Candur(®) SH+P, Hoechst Rousell Vet GmbH), the virus was found to differ from the commonly used vaccine strain, Onderstepoort (93.0% nt and 91.7% aa), and to resemble more closely (99.6% nt and 99.3% aa) a CDV strain detected in China from a Lesser Panda (Ailurus fulgens). An additional four CDV strains matching (>99% nt identity) the Rockborn virus were identified in the sequence databases. Also, Rockborn-like strains were identified in two vaccines currently in the market. These findings indicate that Rockborn-like viruses may be recovered from dogs or other carnivores with distemper, suggesting cases of residual virulence of vaccines, or circulation of vaccine-derived Rockborn-like viruses in the field.

More on Hans Biberstein and his original ideas of vaccination against human warts and herpes infection.

This article presents less known aspects of Biberstein scientific activity. Biberstein pioneered the idea of producing a vaccine against human papillomavirus induced warts and he recognized the fact that there were different types of HPV induced lesions.

The challenge of eliminating cervical cancer in the United States: a story of politics, prudishness, and prevention.

Exciting strides in reducing the incidence of and mortality from cervical cancer have been made over the last century in the United States. The issues surrounding the implementation of the human papillomavirus vaccine are remarkably similar to the issues involved in the gradual adoption of the Pap test and initiation of cervical cancer screening beginning nearly a century ago. The following review of the reduction of cervical cancer morbidity and mortality demonstrates the importance of the interplay between basic science, clinical medicine, social mores, and public policy.

[Sixty years ago, cell cultures finally permitted the poliomyelitis virus to multiply easily]. / Il y a 60 ans (1949), les cultures cellulaires permettaient enfin de multiplier aisément les virus de la poliomyélite.

In 1949, three American virologists, John F. Enders, Thomas H. Weller and Frederick C. Robbins, from the Harvard Medical Scholl and working at the Children's Medical Centre, Boston, Mass., have provoked a true revolution in Virology. Here, they have succeeded in readily multiplying the three poliomyelitis viruses in vitro, in non-nervous cells cultures. A few years afterwards (1954), they were collectively honoured by the Nobel Prize of Physiology and Medicine. This discovery not only has quickly led to the production of efficient poliomyelitis vaccines (J. E. Salk, 1953; A. B. Sabin, 1955) but also has permitted to easily isolate a number of already known viruses (measles, rubella, mumps, herpes simplex and herpes zoster) or until then totally unknown viruses (adenovirus, echovirus, cytomegalovirus). These progresses have significantly contributed to improve diagnosis, sanitary surveillance and vaccinal prophylaxis of human and animal viral diseases. Moreover, the cells cultures techniques have also benefited to other domains of fundamental Biology, such as cellular biology, genetics, cancerology, biology of the reproduction and regenerative medicine as well.

Human cytomegalovirus vaccine: time to look for alternative options.

In 1999, the Institute of Medicine (IOM) of the National Academy of Sciences (USA) assigned the highest priority for a vaccine to prevent congenital human cytomegalovirus (HCMV) infection, on the basis of the life-time cost to the health care system and the impact of the virus on human suffering. Subsequently, this priority was also endorsed by the US National Vaccine Program Office, which proposed a series of recommendations including support for increased funding by government agencies for HCMV vaccine research. Despite numerous attempts over the past three decades, successful licensure of a HCMV vaccine formulation remains elusive. Here we review the current status of HCMV vaccine studies and, based on our recent understanding of immune regulation of HCMV infection, we argue that a more realistic goal for vaccine strategies should be preventing HCMV disease rather than infection.

Fowlpox virus as a recombinant vaccine vector for use in mammals and poultry.

Live vaccines against fowlpox virus, which causes moderate pathology in poultry and is the type species of the Avipoxvirus genus, were developed in the 1920s. Development of recombinant fowlpox virus vector vaccines began in the 1980s, for use not only in poultry, but also in mammals including humans. In common with other avipoxviruses, such as canarypox virus, fowlpox virus enters mammalian cells and expresses proteins, but replicates abortively. The use of fowlpox virus as a safe vehicle for expression of foreign antigens and host immunomodulators, is being evaluated in numerous clinical trials of vaccines against cancer, malaria, tuberculosis and AIDS, notably in heterologous prime-boost regimens. In this article, technical approaches to, and issues surrounding, the use of fowlpox virus as a recombinant vaccine vector in poultry and mammals are reviewed.

Vaccines in historic evolution and perspective: a narrative of vaccine discoveries.

The sciences of vaccinology and immunology were created only two centuries ago by Jenner's scientific studies of prevention of smallpox through inoculation with cowpox virus. This rudimentary beginning was expanded greatly by the giants of late 19th- and early 20th-century biomedical sciences. The period from 1930 to 1950 was a transitional era, with the introduction of chick embryos and minced tissues for propagating viruses and rickettsiae in vitro for vaccines. Modern vaccinology began about 1950 as a continuum following notable advances made during the 1940s and World War II. Its pursuit has been based largely on breakthroughs in cell culture, bacterial polysaccharide chemistry, molecular biology, and immunology which have yielded many live and killed viral and bacterial vaccines plus the recombinant-expressed hepatitis B vaccine. The present paper was presented as a lecture given at a Meeting of the Institute of Human Virology entitled A Symposium on HIV-AIDS and Cancer Biology, Baltimore, Maryland, on August 30, 1999 and recounts, by invitation, more than 55 years of vaccine research from the venue of personal experience and attainment by the author. The paper is intentionally brief and truncated with focus only on highlights and limited referencing. Detailed recounting and referencing are given elsewhere in text references 1 and 2. This narration will have achieved its purpose if it provides a background of understanding and guidelines that will assist others who seek to engage in creation of new vaccines.

Grease, anthraxgate, and kennel cough: a revisionist history of early veterinary vaccines.

In conclusion, it is remarkable just how farsighted many of the early vaccine investigators were. Jenner was apparently very comfortable with contagion and even recognized that infectious agents could gradually change and adapt to a new species. Pasteur, long before his fowl cholera experiment, dreamed that attenuation could yield safe vaccines and it took him no time at all therefore to recognize the significance of that serendipitous experiment. The fact that two other investigators were also developing anthrax vaccines simultaneously is yet another example of how the times favor certain discoveries. Finally Ferry, while constrained by the fact that he had no idea that distemper was caused by a virus, recognized well the concept of secondary infection and rationalized, not unreasonably, that his vaccine might assist in controlling this. It is also clear that we must look skeptically at the accepted historical record. Thus, it is clear that Jenner used horse-derived material as a source of vaccine material and that vaccinia may in fact be the long-lost agent of horsepox. Certainly this would not be news to many nineteenth-century investigators and veterinarians. Individuals planning to use live vaccinia in recombinant vaccines may wish to keep this in mind. Who discovered anthrax vaccine? Burdon-Sanderson clearly recognized that he could attenuate the organism. Greenfield showed that this could protect against disease although he was far from developing an effective vaccine. Poor Henri Toussaint was probably the first to develop an effective product but did not publicize his results widely. It was left to Louis Pasteur to take the risks inherent in a high-profile public experiment and win. I believe that he richly deserves the prize. Finally, who deserves the credit for distemper vaccine? First, Carré deserves much more credit than hitherto for discovering that distemper was caused by a virus. Second, Ferry, although misled by his identification of B. bronchiseptica deserves credit for realizing that his vaccine could play a role in controlling secondary infections. The true discoverer of an effective distemper vaccine was the Italian, Puntoni, but once again the publicity went to others, Laidlaw and Dunkin. Thus a pattern emerges that prior discovery matters little in the face of aggressive publicity. If nobody knows you did the experiment you might as well have never done it in the first place. Publish or perish is by no means a new phenomenon.

Historical vignette: a life with poxviruses and publishers.

Although I started science investigating the physical anthropology of Australian aboriginals and then spent six years in the Australian Army during the 1939-45 war, largely working on malaria control, the poxviruses have been the focal point of my research--at the bench, in the field, on committees, and in front of my word processor. I have had a relatively short period as a scientist at the bench, just over twenty years out of the sixty years since I graduated. For the last thirty years the pipette has been replaced by the pen and the word processor, and contacts with publishers have become an important element in my life. My pilgrim's progress, from mousepox through myxomatosis to vaccinia and then smallpox, has been helped by what can only be described as good luck, coming in many guises. I have been fortunate in many ways; in my father and mother and the genes and family life they gave me; in my wife, who was an immense source of support until her death in 1995; in the people whom I met during the Second World War; and in my close association with three great scientists, Macfarlane Burnet, René Dubos, and Howard Florey. I had the good fortune to be appointed, as a young and inexperienced virologist, to one of the best research jobs in the world, as a professor in the Australian National University. I have been very lucky in having had the opportunity to exploit a series of scientific gold mines; in turn, malaria, during the War, then mousepox, an unexploited virus because its use was forbidden in the United States, then, after a brief flirtation with mycobacteria, myxomatosis, an unparalleled natural experiment of evolution in action, and finally the most impressive achievement in public health in world history, the global eradication of smallpox. My last job in the University before retirement provided me with the opportunity to do something about the most important problems confronting humankind: the degradation of the environment, driven by the explosion in human numbers and their ever-growing use of resources. Each of these activities has provided opportunities to establish and maintain close friendships with scientists all over the world.

Live fish vaccines: history and perspectives.

In the development of live vaccines against enzootic fish viral diseases, the conventional approaches, although somewhat successful, failed finally to deliver efficient, safe, and tagged strains for vaccine application. The genetically-engineered vaccine approach also gave similarly disappointing results. Faced with these realities during our work with VHS, we turned our research effort towards understanding the molecular basis of virulence and antigenicity of the virus. Using sequence analysis of neutralization-escape mutants, we identified several amino acid positions on the glycoprotein which seemed to be involved in the pathological process. The attenuated phenotype was consistently associated with simultaneous mutations at two distant regions, 125-140 and 430-433 of the glycoprotein. We also demonstrated that reversion to virulence was accompanied by the loss of the concurrent mutations, which confirmed their involvement in virulence. The importance of these two regions of the glycoprotein was confirmed by the finding that laboratory or naturally attenuated variants had mutations within these regions. Using the same methodology, we selected mutants from an attenuated temperature resistant variant (tr25), which had previously been developed in our laboratory. Virulence, antigenicity and protective activity of the further attenuated mutants were evaluated in fish of different size by intramuscular (i.m.) or water bath administration. Strains having an additional mutation at position 139 were completely non-virulent for fish of 1000-1400 degree-days (dxd) by bath. These mutants retained their immunogenicity and had a thermo-resistant, an antigenic, and five genetic markers. Thus, they will constitute ideal candidates for live vaccine development, once their protective activity and containment have been confirmed in field trials.

Safety of biopharmaceuticals: a current perspective.

The impetus for this conference comes in large measure from the continuing development of the ICH Viral Safety document concerned with testing and evaluation of the viral safety of biotechnology products derived from characterized cell lines of human or animal origin [1]. My opening remarks for this conference were, I think, suggested by the organizers in the belief that George Santayana's quote, "Those who cannot remember the past are condemned to repeat it" has validity for this effort. In this brief review I have tried to recall some past unfortunate episodes and outline the lessons that they might have for us. I have also attempted to outline a number of issues which I believe are critical to the success of efforts to guarantee, as much as humanly possible, the safety that we seek balanced against our ability to develop and use important new products.