Serine requirement in leukemic and normal blood cells

In a serine-deficient medium, cells from humangt chronic granulocytic leukemia and normal human bone marrow exhibited a marked inhibition of incorporation of-radioactive precursors of DNA, RNA, and protein into an acid insoluble cell fraction. Normal diploid human fibroblasts did not exhibit inhibition without serine. Chronic granulocytic leukemia and normal marrow cells were essentially unable to synthesize C(14)-serine from C(14)-glucose, while human diploid fibroblasts were highly capable of this synthesis.

Studies on Serum-Fractions

The finding by Hektoen and Welker and by Taylor that the increase of globulin in diphtheric antitoxins was demonstrable by the precipitative reaction was confirmed with the use of antisera prepared by immunizing rabbits with the washed floccules of diphtheric toxoid-antitoxin.

The amount of protein precipitable by diphtheric toxin from antidiphtheric horse-sera in the indicating mixture was found to be roughly proportional to the antitoxic units determined by titration in vitro; but the amount of the component reacting with antiserum prepared against diphtheric antitoxin-globulin does not parallel the antitoxic potency.

Studies on Serum-Fractions

It was shown in a series of reports (a) that antihorse-serum precipitin can be produced by immunizing rabbits with antigen-antibody (immune horse-serum) complexes (1), (b) that two fractions, “A” and “B”, related to antibodies can be distinguished (1, 2) and (c) that antibody-globulins (diphtheric antitoxin-globulin and pneumococcal antibody-globulin) constitute only a part of these fractions (4). It was also shown that antitoxic immunization seems to cause an increase in the A-fraction (a fraction reacting with antiserum against antitoxic globulin) whereas antibacterial immunization seems to be followed by an increase in the B-fraction (which reacts with antiserum prepared with the specific precipitates of pneumococcal SSS) (2). This would seem to indicate a possible antigenic relationship of different antibacterial antibodies on the one hand and of different antitoxins on the other.

In this report we deal with the relation between the B-fraction and pneumococcal, typhoidal, Shiga-dysenteric and plague-antibody globulins.

Studies on Serum Fractions

Diphtheric antitoxin is precipitable by the precipitating serum prepared with the floccules of diphtheric toxoid-antitoxin (P.V.At.), whereas pneumococcal antibody is precipitated by the precipitating serum prepared with specific precipitates of pneumococcal SSS (P.V.Ab.) in their optimal proportions and also in the range of excessive precipitin. The former precipitating serum absorbs also antipneumococcal antibody from antipneumococcal horse serum, but it is only in the range of the mixtures containing far less antipneumococcal serum than the quantity present in the optimal proportion. The latter precipitating serum absorbs also antitoxin from antidiphtheric horse serum, but this absorption occurs only in the secondary zone and not in the primary or main zone.