May 21, 1942

Dr. Edwin J. Cohn

Harvard Medical School

Boston, Massachusetts

Dear Dr. Cohn:

We have just been granted a contract by the Committee on Medical Research for the investigation of the possibility of treating antigenic protein solutions with chemicals such as bis diazotized benzidine or other bifunctional reagents so as to mask their antigenic groups. This is a pretty long shot, and I am not expecting favorable results from the first trial. Dr. Hastings told me that you had made some experiments along these lines, and I would be very glad indeed to know what they were and what results were obtained.

We have been helped in our artificial antibody work by having at hand the supply of bovine gamma-globulin which Armour and Company sent us with your permission, and I want to thank you again for making this arrangement for us. it would be very useful if we had for our masking project various fractions of the bovine serum proteins. Dr. Richards has suggested that I ask you if you could supply us with these fractions. I think that the fractions on which we might work most effectively would be those bordering on your non-antigenic albumin fraction, about which I have obtained only brief word-of-mouth reports. Thus if you had available in large quantity a fraction which was antigenic but only slightly so, we might be able by relatively simple chemical treatments to remove the antigenicity. I would be very glad indeed to have your opinion about this matter and about the project as a whole, and also I would be very grateful to you if you could provide us with fractions of bovine serum proteins.

The personnel for this project has not yet been settled. It is probable that Dr. J.B. Koepfli, Dr. Carl Niemann, and Dr. Dan H. Campbell will spend smaller or greater parts of their activities on this work. We propose as a first step in the investigation to determine the antigenicities of proteins, using rabbits as test animals, and then to see if there is any loss in antigenicity on chemical treatment.

I have also another request to make of you. As I mentioned in my letter last summer, we would like to try to human gamma-globulin as the raw material for artificial antibody manufacture. Some time ago Dr. Koepfli received a letter from Mansfield Clark of the National Research Council asking if we had need for human serum fractions other than albumin. At my request he answered that we would like to have some human gamma-globulin, but although he has been busy writing letters about the matter no results have been obtained.

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I think that perhaps your Laboratory would have been the primary source of the material, and that I should have written to you again about it. So now I ask if it would be possible for us to obtain a reasonable amount, of the order of magnitude of 50 grams, of human gamma-globulin or some similar fraction for use in this other investigation, dealing with the manufacture of antibodies in the laboratory.

It has been a long time now since I have come to Boston, and I have no plans to make such a visit soon, but I hope that we may get together one of these days. Please give my respects to Dr. Edsall.

Sincerely yours,

Linus Pauling

LP:jr