Effects of in vivo neuraminidase on the regulation of erythropoiesis II: Modulation of erythroid colony formation by thymic regulatory cells

V. F. La Russa, L. L. Sensenbrenner, S. J. Sharkis

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4 Scopus citations


Effects of the enzyme vibrio-cholerae neuraminidase (VCN) on the marrow-derived erythropoietic progenitor CFU-E and thymic regulatory cells were examined in vitro 1 and 24 h after i.v. injection of the enzyme. An in vivo enzymatic modification of bone marrow and thymic helper regulatory cell function occurs within 1 h after i.v. injection of VCN and results in suppression of both CFU-E colony formation and thymic helper cell function. These inhibitory effects of neuraminidase, however, are no longer detectable by 24 h after injection. More importantly, these inhibitory effects can be reversed by adding thymocytes from control animals to cocultures of enzymatically modified marrow or thymic regulatory cells. These findings: 1) suggest that regulatory cells from the bone marrow and thymus may be enzymatically modified in vivo in a reversible manner, suggesting a noncytotoxic effect of the enzyme on accessory cells, and 2) confirm the importance of sialic acid for the helper function but not for the suppressor function of thymocytes and CFU-E colony formation in vitro.

Original languageEnglish (US)
Pages (from-to)106-109
Number of pages4
JournalExperimental Hematology
Issue number2
StatePublished - Jan 1 1989


ASJC Scopus subject areas

  • Molecular Biology
  • Hematology
  • Genetics
  • Cell Biology
  • Cancer Research

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