January 2, 1941
Dr. Warren Weaver
The Rockefeller Foundation
49 West 49th Street
New York, New York
Dear Warren:
I am writing now to ask your advice about our research program in immunology.
First let me say that the work in organic chemistry and structural chemistry is going along well. Zechmeister, with two
post-doctorate assistants and four graduate students, is making headway on several problems. He has fitted into our department
satisfactorily, and there has been no trouble at all of the sort that sometimes accompanies the appointment of a European
professor. Carl Niemann is working as hard as ever and as effectively. The molecular structure program is booming along.
The crystal structure of alanine, now completed, has turned out to be especially interesting. In this crystal for the first
time the positions of hydrogen atoms were verified by the x-ray data. We are now beginning to get good x-ray photographs
of large polypeptides, with fifty or one hundred amino acid residues per molecule, and I think that we shall succeed in making
complete structure determinations of these. At present we are studying polyglycines, and Dr. Edsall, who is here this year
as Guggenheim Fellow, is now preparing some polypeptides containing both glycine and alanine. I am confident that this method
of attack, using synthetic polypeptides of known amino acid composition, which might be called artificial proteins, will lead
ultimately to the solution of the protein problem.
For about six months Dr. Dan Campbell, Rockefeller Fellow, and Dr. David Pressman have been working with me on experimental
problems in immunology. This work has moved along slowly, because of its nature, but I am pleased with the results obtained.
It was fortunate for us that Dr. Campbell was here. Dr. Pressman, an organic chemist trained here, was supported in part
from the Rockefeller Foundation and in part from the Noyes Fund of the Institute. All together we have used about $2000
of this year's Rockefeller budget for the work in immunology. The researches completed or under way are the following.
1. Serological reactions with simple substances containing two or more haptenic groups. We have shown, verifying the work
of Landsteiner and van der Scheer, that simple substances containing two or more haptenic groups will give the precipitin
reaction with homologous antiserum and produce shock in sensitized guinea pigs. Hooker and Boyd had said that they could
not obtain reactions of this type. We have made quantitative studies of the precipitin reaction, determining the amount
of antibody nitrogen precipitated by the micro-Kjeldahl method. So far we have positive results for six substances involving
arsanilic acid residues attached to resorcinol or phloroglucinol. These results are described in a paper which Campbell,
Pressman, and I have published in the Proceedings of the National Academy of Science. The production of a precipitate by
simple substances containing two or more groups is, I think, a very strong argument for the framework theory of antibody-antigen
precipitates.
2. The manufacture of antibodies in vitro from normal serum proteins. In my paper I suggested that it should be possible
to manufacture antibodies in vitro by denaturing serum proteins and slowly renaturing them in the presence of antigen. Experiments
along these lines have been carried out, using three different fractions of beef globulin and the dye methyl blue as antigen.
It was found that after denaturation of the protein with alkali or by heat slow renaturation in the presence of the dye produced
a protein solution which combined with the dye much more strongly than protein solutions obtained in other ways, such as by
rapid renaturation in presence of dye or by various treatments in absence of dye. Similar experiments were started here
with bacteria as antigen, and Dr. Campbell plans to continue them in Chicago. Further work is needed to test the specificity
of the artificially produced antigens, but the results obtained already are positive.
3. A quantitative study of sera homologous to antigens containing two different haptenic groups. Landsteiner reported experiments
suggesting that no antibody molecules of type A'-B' were present in the serum produced by antigens containing two different
groups A and B. This result is incompatible with my theory or any theory involving bivalent or multivalent antibody molecules.
With the cooperation of Dr. Landsteiner, we have been carrying out quantitative studies of his sera, and have obtained results
which support the conclusion opposite to that reached by him.
4. The theory that agglutination is the result of the clasping together of cells by bivalent antibody molecules requires that
inhibition of agglutination occur on treatment of cells by a sufficiently strong agglutinin solution. Hooker and Boyd have
reported failure to produce agglutination in erythrocytes and argue accordingly against the bivalent antibody theory. We
are carrying out agglutination experiments using antiarsanilic acid serum as agglutinin and erythrocytes treated with diazotized
arsanilic acid as the cells.
There are many other experiments which we plan to carry out. These include the quantitative study of antibody-antigen composition
of precipitates, the determination of equilibrium constants and heats of reactions by physical-chemical methods, especially
by the use of various haptens for the study of soluble complexes, the separation of antibodies of different kinds by combination
with charged haptens and subsequent electrophoresis, the investigation of the order of the reaction of antibody production
by quantitative studies of serum titer for large numbers of rabbits immunized by different amounts of antigen, etc. We are
handicapped at present by our inability to determine the amounts of antigens, especially those containing arsenic, in small
precipitates with sufficient accuracy. This problem can be solved easily by the use of radioactive arsenic (the isotope
As74 made from germanium by deuteron bombardment, with sixteen-day half life), and Edwin McMillan has arranged for this to
be made for us in Berkeley when we are in a position to use it effectively.
I feel enthusiastic about the program of research in immunology, and I would like to carry it on vigorously for some time
in the future. In addition to the experiments mentioned above, we have many others under consideration, some of which have
been suggested by the immunologists who have written to me since the appearance of my paper. I have, in fact, been carrying
on a rather lively correspondence with immunologists of the country, especially with Dr. Boyd in Boston, who is strongly opposed
to my theory in so far as it involves bivalent antibodies. I find that immunological work is laborious, and that it moves
along slowly unless a suitable number of assistants are available. I am afraid that it would not be possible to take from
our present funds enough money to permit the work to be done effectively— we got along this year because of our accidental
good fortune in having Dan Campbell here.
The program which I have in mind would involve the expenditure of about $20,000 per year, with the following budget:
Research Fellow, Immunology $3000.00
Research Fellow, Organic Chemistry 2400.00
Research Fellow, Physical Chemistry 2000.00
Assistant, Immunology 1500.00
Assistant, Organic Chemistry 1200.00
Assistant, Microanalysis and Radioactivity 1400.00
Apparatus, supplies, animals 7500.00
Expenses of visiting professor 1000.00
Total $20,000.00
As Research Fellow in Immunology I would like to have Dr. Dan Campbell, at present Assistant Professor of Bacteriology and
Immunology at the University of Chicago. He is a good technician in the field, an industrious man who works steadily day
after day, and a man with interest in chemistry and with an open mind regarding science. I doubt that a better man could
be found for this appointment. As Research Fellow in Organic Chemistry I would suggest Dr. David Pressman, who has been
carrying on this work this year, and has become deeply interested in immunology. He has been helped in the preparation of
organic substances this year by two seniors in chemistry, the two best men in our senior class. Both are American-born Japanese.
I think that one might be kept on next year full time as assistant in organic chemistry. The item of $7500.00 for apparatus,
supplies, animals would permit us to use the large number of animals required for some of our projected researches, and should
permit also the construction of a Tiselius apparatus for the electrophoretic separation of antibody fractions by the suggested
method of combination with charged haptens, and for other investigations. I have included the item $1000.00 for expenses
of a visiting professor. It seems to me that one of the best ways of assuring that we were making an effective attack on
immunological problems would be to bring here each year some authority in the field, for discussion and collaboration. This
would be of value also to the people here in biology.
I would like to be able to plan to carry on this program over a five-year period.
Would you please tell me whether you think that it would be worth while for an application along these lines to be submitted
to the Rockefeller Foundation and if so in what respects the application should deviate from the outline given in this letter.
I would like our attack on the problem to be intensive enough to be effective, and the program which I have described above
is, I think, just about right.
With best regards, I am
Sincerely yours,
Linus Pauling
LP:jr
