Letter from Michael Heidelberger to Jacques J. Bronfenbrenner, Washington University School of Medicine
As illustrated by this letter, Heidelberger and his colleagues conducted detailed discussions and evaluations of experimental
results, here with regard to antibody-antigen interaction, through frequent correspondence.
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3 (272,315 Bytes)
1943-10-29 (October 29, 1943)
Bronfenbrenner, Jacques J.
[Washington University School of Medicine]
This item is in the public domain. It may be used without permission.
Medical Subject Headings (MeSH):
Antigens and Antibodies: Heidelberger and The Rise of Quantitative Immunochemistry, 1928-1954
Letter from Jacques J. Bronfenbrenner, Washington University School of Medicine to Michael Heidelberger (November 8, 1943)
Some time ago I read, with great attention and interest, the two papers in the May J. Immunol. by your group and put them
aside for further study. An enforced day in bed gave me the opportunity yesterday, and goaded by your challenge beginning
at the bottom of p. 288, I made a few calculations, with the following result:
First, let me say that the "contrary finding. . .with anti-Ea" is not an isolated result, as you infer: it was equally
definitely shown with Kabat (J. Exp. Med., 1937, 66, 229, esp. Table V) in the horse serum albumin-rabbit anti-HSA system,
and at the S.A.B. meeting in 1940 (J. Bact. 39, 37) Mayer and I told of the presence of 10 percent or more "univalent"
antibody in other systems. Now, to add to this, we have your own date, which clearly show the inhomogeneity of rabbit antiphage,
unless I, too, have entirely misinterpreted them, as I believe you have.
Taking as a basin the antibody content of antiserum 29 as 0.6 mg. A N per ml. (Table 2 and p. 271 of Paper 1) and the statement
on p. 288 that about 40 percent A had been removed from 29A, let us get to work on the pertinent portion of Table 2 on p.
etc., with the results naturally approaching each other as one nears 100%.
At equal A content, the only point at which comparisons are permissable, it seems quite clear that whole anti-phage has been
very different combining ratios from anti-P with the "cream" skimmed off. You will note, too, that this comparison
is made in the region of A excess, where we also made ours. Comparison at the 50% P neutralization and are not competent
to decide this point, as you seem to think (Fig. 1, etc.), for in the antigen-excess region A-antigen ratios are much lower,
and even with quantitative N estimations in error by only a very few % it is difficult to decide between, let us say, 3.3
and 3.0 Another very clear demostration of the in homogeneity of A (which you use to show just the opposite) is also given
in your Table 4. Here, I take it, if you use Fig. 1, although this has to be dug out of the text and is not stated as ordinate,
"expected neutra" and "obsd. Neutra." refer to P, not A. If this is correct, these two columns are crucial,
for as a rule the observed values are notably higher than the calculated, as I could have predicted from our work. As you
see, the lower-ratio A combines with more P per [symbol] than does "whole" A.
Again, it seems to me the values of k in Table 3 of Paper 1 also clearly show the difference between whole and partly absorbed
29 for if k is a function of the A content, as you say, and doubles in the case of Serum 1 when Po goes from 10 [to the sixth]
to 10 [to the ninth] the two k's for 29 and 29A should be about equal. However, they are nearly as 2:1!
Taking up another point, the size of P, which may apparently vary from the intriguing forms shown in the electron microscope
down to 50,000 or so, why need one stop at 27 lytic units? Stokinger and I showed (J. Exp. Med., 37, 66, 251) that in the
region of A excess with thyroglobulin of M.W. 750,000 TgA40 was easily possible. Tg is apparently a disc (Svedberg said "a
pancake"), so that it requires little imagination to stick 40A on to it, especially end on. Tg also dissociates on dilution.
If P is not spherical and is way up in the millions, why not 4630A? That is only 100 times TgA40 and would only make P=100
x 10 [to the sixth].
However, I am not very much at home with phage and found myself unable to be as sure about P as about A. However, since you
were also very sure about A, I'm still a little worried about some of these calculations regarding P as well. You see,
as I wrote to Hershey, I never could subscribe to that third precipitin reaction paper, and what you've done in this is
following out the idea of antibody homogeneity makes it more apparent that the evidence lies all the other way.
However, it's possible that my arithmetic is bad, so I'll be much interested in your come-back. More power to you
if you can drive it home! And because I don't agree with you on A, don't that I'm not filled with admiration
at the beautiful new technical methods you've introduced and the accuracy and reproducibility with which you now can handle
With cordial greetings to you all,
P.S. My former student and collaborator, Manfred Mayer, makes the following additional observations:
The necessity for the parallelism of the cruves in Fig. 1 if the sera differ only in A content should be proved, not stated,
since the exact function connecting A and neutralization is not known. For example, equations such as we use indicate the
A content of 2 different sera to vary as the squares of the P concentrations, giving similar % neutralization.