International Journal of Cell Cloning, Vol 1, 130-141, Copyright © 1983 by AlphaMed Press
Effects of OKT3+, OKT4+ and OKT8+ T cell subsets on steady-state granulopoiesis in vitro
S Koizumi, M Yamagami, S Horita, M Miura, M Sano, N Ikuta and N Taniguchi
The present study was undertaken to elucidate the role of T cell subsets in
regulating the in vitro growth of human granulopoietic progenitor cells
(CFU-C). Prior to CFU-C assay, mononuclear cells obtained from bone marrow
and cord blood were depleted of T cells or functionally distinct T cell
subsets by the method of complement- mediated cytolysis with the use of
monoclonal antibodies, OKT3, OKT4 and OKT8. The depletion of any T cell
subset of OKT3+, OKT4+ or OKT8+ cells from bone marrow and cord blood cells
showed no significant alterations in the generation of CFU-C. The
supplementation to the in vitro culture system of OKT4+ or OKT8+ cells,
which had been negatively selected by complement-mediated cytolysis using
the mutually exclusive monoclonal OKT8 or OKT4 antibody, respectively, did
not alter the growth of CFU-C-derived colonies without mitogenic
stimulation. In contrast, the production of colony-stimulating activity
(CSA) in peripheral blood mononuclear cells was significantly reduced by
removing not only OKT3+ cells but also OKT4+ or OKT8+ cell subsets. There
were no significant differences in the degree of reduction between the
different procedures. These results suggested that T cell subsets played an
important role in the regulation of steady-state granulopoiesis through the
stimulation of CSA production. The presence of a specific subset of T cells
in CSA production was not demonstrated.
