Abstract
Serum from mice bearing five weakly immunogenic or nonimmunogenic tumors inducing concomitant resistance exhibited a growth-inhibitory activity on in vitro proliferation of the tumor cells. This activity was proportional to the intensity of concomitant resistance and correlated with the capacity to restrain metastatic development. It was not attributable to cytotoxic antibodies, was relatively nonspecific, and operated through a cytostatic and reversible mechanism. All attempts to transfer antitumor resistance in vivo by serum inoculation have failed, but this could be attained by parabiosis. Physical and chemical serum treatments suggest that heat-, acid-, and alkali-resistant peptide(s) with molecular weights ranging from 1000 to 3000 could account for this inhibitory effect.
Footnotes
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↵1 This study was supported by national grants from CONICET, FUNDALEU, Fundación Antorchas, and Fundación Alberto J. Roemmers.
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↵2 To whom requests for reprints should be addressed.
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↵3 Member of Research Caceer, CONICET (Consejo Nacional de Investigaciones Cientificias y Técnicas).
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↵4 Fellow of FUNDALEU (Fundación para Combatir la Leucemia).
- Received January 18, 1990.
- Accepted July 30, 1990.
- ©1990 American Association for Cancer Research.
Volume 50, Issue 22
