19 June 1953
Dear Dr. Gordon:
Under separate cover we are sending you a reprint of my 1940 paper, and also some of our recent protein papers, and one on sickle cell anemia hemoglobin.
I have stopped working on the problem of artificial antibodies mainly because some other subjects have engrossed my interest. Also, I have been disappointed in our failure to manufacture artificial antibodies that show protective power against disease. We have carried out a number of experiments in an effort to manufacture protective artificial antibodies. One preparation, of antipneumoccus antibodies, seemed to have significant protective power against disease. However, we have never been able to repeat the preparation of significantly active protective artificial antibodies, and I think now that the combining powers of our artificial antibodies are so weak, in comparison with natural antibodies, that it is difficult to observe protective power.
One interesting new development is the manufacture of specific inorganic absorbents, to order. This work was carried out by a student here, Dr. Dickey, and is published in the Proceedings of the National Academy of Sciences 35, 227 (1949).
I am sorry that the work that we began on artificial antibodies has not turned out to be promising for protection against disease. I feel, nonetheless, that it is of some value in giving a better insight into the nature of the protective mechanism.
Sincerely yours,