The production of granulocyte-monocyte colony-stimulating activity by
isolated human T lymphocyte subpopulations
PJ Hesketh, R Sullivan, CR Valeri and LA McCarroll
Isolated human T lymphocyte subpopulations were obtained by
fluorescence-activated cell sorting using the murine monoclonal antibodies,
OKT4 and OKT8. The capabilities of the isolated lymphocytes to produce
granulocyte-monocyte colony-stimulating activity (CSA) in response to
mitogen challenge were assessed by in vitro assays employing light density
nonadherent bone marrow cells. Essentially, no CSA production was noted by
any isolated T lymphocyte population [OKT4 positive (+) or OKT8 positive
(+)] cultured alone or following the addition of 10(4) autologous
monocytes/ml. When phytohemagglutinin (PHA) alone was added, OKT4+
lymphocytes elaborated small amounts of CSA. With the addition of
concanavalin A (Con-A) alone, both OKT4+ and OKT8+ cells were able to
produce modest amounts of CSA. Significantly enhanced CSA production was
observed when either OKT4+ or OKT8+ lymphocytes were coincubated with
autologous monocytes in the presence of mitogen. We conclude that highly
purified T lymphocyte subpopulations, free of monocytes as assessed by
nonspecific esterase staining, can elaborate small amounts of CSA in
response to PHA or Con- A challenge. A synergistic augmentation of CSA
production was noted with coincubation of sorted lymphocytes and autologous
monocytes in the presence of mitogen. Finally, our results suggest that the
ability of T lymphocytes to make CSA is not exclusively limited to either
the OKT4+ or OKT8+ defined subsets.
Volume 63,
Issue 5,
pp. 1141-1146,
05/01/1984
Copyright © 1984 by The American Society of Hematology
