NEW METABOLIZABLE IMMUNOLOGIC ADJUVANT FOR HUMAN USE. 2. SHORT-TERM ANIMAL TOXICITY TESTS

Personal historical chronicle of six decades of basic and applied research in virology, immunology, and vaccinology

The sciences of vaccinology and of immunology were created just two centuries ago by Jenner's studies of prevention of smallpox by inoculation with cowpox virus. This rudimentary beginning was expanded greatly by the giants of late 19th and early 20th centuries 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 era vaccinology began about 1950 as a continuum of notable advances made during the 1940s and World War II. Present vaccinology is based largely on breakthroughs in cell culture, bacterial polysaccharide chemistry, molecular biology, and immunology. By invitation, the author, who is a microbe hunter in fact, was asked to chronicle his six decades of pioneering achievements in basic and applied virology, bacteriology, immunology, molecular biology, epidemiology, and cancer, with special reference to the pioneering creation of most of the present day vaccines. Knowledge of the past may guide the present and future. This chronicle will have achieved its legacy if it helps others to understand the why and how of the past that may help to create the substance of the future.

[Influenza]

Influenza is the last great uncontrolled plague of mankind. Pandemics and epidemics occur at regular time intervals. The influenza viruses are divided into the types A, B and C and show unique variability of their surface antigens (hemagglutinin and neuraminidase). Influenza viruses of type A show the largest degree of antigenic variation which, in turn, resulted in the definition of a number of subtypes, each comprising many strains. By comparison, influenza viruses of types B and C exhibit much less variation of their surface antigens. As a consequence, no subtypes but many different strains have been recognized. The degree of antigenic variation correlates with the epidemiologic significance of the virus types, type A being the most and type C the least important. Two different kinds of antigenic variation have been recognized: In the case of minor variation of one or both surface antigens, the term "antigenic drift" is employed. Antigenic drift occurs with all three types of virus, it is caused by point mutations which increase the chance of survival of mutants in the diseased host. In addition, influenza A viruses show sudden and complete changes of their surface antigens in regular time intervals, resulting in the appearance of new subtypes. This event is called "antigenic shift". The mechanisms responsible for antigenic shift are poorly understood, only. In addition to the recycling of preceding subtypes, reassortment resulting from double infection of cells with strains of human and animal origin are considered possible explanations. By use of modern DNA recombinant technology, the base sequences of a series of virus genes and, as a consequence, the amino acid sequence of the corresponding antigens have been determined. By means of monoclonal antibodies, the antigenic structure of many influenza antigens has been further elucidated. It can be expected that further research on the molecular basis of antigenic variation could finally result in an understanding of the causal mechanisms. It is an outstanding feature of the epidemiology of influenza A viruses that a family of related strains prevails for a certain period of time and disappears abruptly as a new subtype emerges.(ABSTRACT TRUNCATED AT 400 WORDS)

An assessment of oil adjuvant and aqueous influenza vaccines. I. Reactions to the vaccines

Trials of aqueous and oil adjuvant vaccines in young adult volunteers showed that severe local reactions were rare. However, the incidence of minor symptoms was too high for a vaccine which requires to be administered repeatedly. In contradistinction to some reports, systemic and allergic reactions did not constitute a problem.