T-Derived colony-inhibiting activity: Partial characterization and mechanism of action1

G. Piaggio, A. Bacigalupo, F. Frassoni, M. Podestà, M. Repetto, A. Risso, E. Cosulich, A. M. Marmont

Research output: Contribution to journalArticlepeer-review


A soluble inhibitor of granulocyte macrophage colony growth, to which we shall refer to as T-derived colony-inhibiting activity (Td/CIA), was obtained from the supernatant of Tcells from 5 healthy donors and 5 patients with severe aplastic anemia (SAA) in remission, following immunosuppressive therapy. The supernatants were purified by an ACA 44 column and the suppressor activity found in fractions of 70,000-80,000 daltons. Experiments were then performed to test for (a) endogenous productions of Td/CIA in normal marrow cells (NBM), (b) reversibility of suppression, and (c) competitive inhibition with human placenta-conditioned medium (HPCM). The results of this study can be summarized as follows: (1) the endogenous production of Td/CIA can be elicited by addition of mitogens to NBM, and is prevented if the marrow is T-depleted or treated with cyclosporin A; (2) suppression is completely reversible if Td/CIA is removed from NBM by washing at 1, 48, 72 and 96 h; (3) CFU-c which have been exposed to Td/CIA once, and freed from Td/CIA by washing, are still sensitive to a second exposure of Td/CIA; (4) there is no clear competitive inhibition between Td/CIA and HPCM. These experiments represent an in vitro model of a lymphokine-mediated regulation of CFU-c growth not associated with death of progenitor cells.

Original languageEnglish
Pages (from-to)195-199
Number of pages5
JournalActa Haematologica
Issue number4
Publication statusPublished - 1985


  • Aplastic anemia
  • CFU-c
  • Lymphokine

ASJC Scopus subject areas

  • Hematology


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