Armstrong – Table of Contents

demonstrated alimentary tract infection in the chimpanzee. They also did extensive
pathology studies of infection in monkeys, and they suggested the probable pathogenesis
of infection in these subjects. In the later 1940s Bodian, Morgan, and Howe were able to
group 14 strains of polio into the three basic types. In 1948-1949, Morgan was able to
immunize monkeys with a formalin inactivated polio vaccine. Prior to all the above
events Armstrong, in 1939, was able to adapt the Lansing strain (type II) of poliovirus to
cotton rats and white mice. This was a major advance in polio investigation since it
opened the way to quantitative measurement of virus and neutralizing antibody on a scale
that was impossible to achieve in monkeys. This provided a major quantitative
epidemiological tool until 1949 when John Enders, Thomas Weller, and Frederic Robbins
adapted a passage of the Lansing strain to grow in tissue culture containing non-neural
tissue.
This latter Nobel Prize winning discovery strongly encouraged the possibility that
an effective vaccine against poliomyelitis grown in tissue culture might be feasible. It
was important, therefore, to determine the exact number of immunological types that
existed. From 1948 to 1952, funded by the Foundation Virus Research Committee,
several prominent research centers received the task and funds to type by immunologic
methods as many of the known isolated poliovirus strains as possible. This activity
resulted in establishing the three polio types: Brunhilde (type I); Lansing (type II); and
Leon (type III).
Among the poliovirus typing center investigators was Dr. Jonas Salk, Director of
the University of Pittsburgh Virus Unit. Dr. Salk was planning and developing
simultaneously a killed polio vaccine much to the objections and criticisms of the virus