Letter from Florence B. Seibert to Florence R. Sabin
Seibert was a fellow member of the National Tuberculosis Association's Research Committee. Here she writes to Sabin with
questions about the immune responses she has obtained by combining tuberculosis proteins and phosphatides.
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1937-02-23 (February 23, 1937)
Seibert, Florence B.
Sabin, Florence R.
Original Repository: American Philosophical Society. Library. Florence R. Sabin Papers
Reproduced with permission of the American Philosophical Society.
Medical Subject Headings (MeSH):
At the Rockefeller Institute for Medical Research, 1925-1938
Seibert, Florence, #2
February 23, 1937.
Dear Dr. Sabin:
The dose of protein which I have been using in the guinea pigs for sensitizing them is 10 mgms. in 0.1 to 0.4 cc. per injection
and each animal received 10 injections. The phosphatide control pigs received 20 mgms. at each injection, and the phosphatide
plus protein pigs received 10 mgms. protein + 20 mgms. phosphatide. This amount of protein seems large but corresponds to
the amount Opie and others usually used for sensitizing animals to other proteins.
At first I gave these injections intraperitoneally because I did not think the phosphatide was irritating, but the pigs began
dying. Grossly there were adhesions, congestion, fluid, fibrin, abscesses and caseous and necrotic areas in the abdomen.
Therefore, I changed to subcutaneous injections and since then they have not died. Locally, there is marked inflammation
and persistent nodules in the skin of those pigs receiving the phosphatide alone as well as in those receiving the phosphatide
So far the skin reactions obtained with 1 mgm. protein in these (protein + phosphatide) pigs are not conspicuously greater
than in those receiving the protein alone, and therefore, increased hypersensitivity has not occurred. The highest degree
of hypersensitivity ever obtained by sensitizing even with the protein is much less than that which occurs in the tuberculous
guinea pig. The strange thing is that the control pigs receiving phosphatide injections alone, give as great or greater skin
reactions to 1 mgm. of the protein than do those receiving protein alone or those receiving protein plus phosphatide. This
is hard to understand. Can you explain it? Is the phosphatide itself antigenic? It seems to be very irritating to the tissues
in comparison with the protein.
Now that the point which I was after seems to be proved in the negative, and it would be wasteful to kill the pigs so prepared,
I believe I will inoculate them with tubercle bacilli and watch them for longevity. It will serve as a check on my previous
experiment with the protein sensitized pigs (Proc. Soc. Exper. Biol. & Med. 1933, 30, 1274) and give a comparison with
the effect of phosphatide on the sensitization. Or have you already done this experiment? I know very little about the phosphatide
reactions and would appreciate your opinion.