Modulation of murine erythropoiesis in vitro by syngeneic thymocytes:
interactions of enhancing and suppressing subpopulations with fluorescent
anti-theta antibody and polyamino acids
F Sieber and SJ Sharkis
As we have shown previously, cocultures of bone marrow cells with large
numbers of syngeneic thymocytes enhance erythroid colony formation in
plasma clots, whereas cocultures with low numbers of thymocytes suppress
erythroid colony formation. In this article, we present evidence that the
enhancing and suppressing functions of thymocytes are most likely mediated
by at least two separate subpopulations. When thymocytes were fractionated
on the basis of cell surface density of the theta antigen, enhancing cells
were limited to the high theta density fraction, whereas suppressing cells
were accumulated in the low theta density fraction. When thymocytes were
fractionated on the basis of negative surface charge, the enhancing cells
were recovered among the more negatively charged cells. A short in vitro
incubation with polyamino acids selectively abrogated the suppressor
function.
Volume 60,
Issue 4,
pp. 845-850,
10/01/1982
Copyright © 1982 by The American Society of Hematology
