Letter from Colin M. MacLeod to Michael Heidelberger
During World War II Heidelberger served as a member of the Pneumonia Commission established by the Board for the Investigation
and Control of Influenza and Other Infectious Diseases (later the Army Epidemiological Board) under the Surgeon General of
the U.S. Army. The Commission, headed by Colin MacLeod, a microbiologist and co-discoverer of the genetic properties of DNA,
organized a trial of a vaccine against pneumococcal pneumonia developed by Heidelberger. The trial, carried out among 20,000
trainees at an air base in Sioux Falls, South Dakota, proved that a vaccine made from a mixture of purified capsular polysaccharides
from four different types of pneumococcus was effective against the disease.
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1941-05-20 (May 20, 1941)
MacLeod, Colin M.
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Medical Subject Headings (MeSH):
Antigens and Antibodies: Heidelberger and The Rise of Quantitative Immunochemistry, 1928-1954
This letter is to confirm our telephone conversation concerning the meeting of the Army Pneumonia Commission at 9:30 a.m.
Tuesday, May 27th, at the
Rockefeller Institute. Since you are a resident of New York City you will not receive Travel Orders from the Surgeon-General's
In our brief conversation in Nashville you may recall that the question of antipneumococcal immunization came up. As I remember
we agreed that the possibilities of prophylactic antipneumococcal vaccination have not been fully explored, particularly from
the point of view of an innocuous and perhaps more effective polysaccharide antigen. It is of course possible to use carefully
prepared vaccines, but the disadvantages of these are obvious. However, it does seem possible that if the polysaccharides
could be rendered less soluble or immobilized in the tissues a little longer their antigenicity might be improved considerably
and at the same time no local or constitutional reaction result. I mention the matter again at this time since it will be
discussed at the meeting of the Commission, and your thoughts on the matter and the approach to it are very desirable. It
is quite possible that an appropriation for supplies and technical assistance for this project will be approved by the Board.
The advisability of general antipneumococcal immunization is open to question in the light of the work that has been done
to date, but immunization in the face of an epidemic may have considerable usefulness, particularly if backed up by adequate
I would appreciate it if you would draw up a tentative program for the interim investigation of this problem, to include estimates
of salaries for technical assistance, for expendable supplies (media, glassware, reagents, etc.) and for durable property
if necessary. As far as technicians are concerned the regulations state that they may be employed without civil service status
up to not more than 60 days continuous employment during any fiscal year. If on part time service, the number of hours of
employment during any one year cannot be more than require payment of $540.00. Otherwise, technicians must be on civil service