Human bone marrow and peripheral blood T lymphocyte depletion: efficacy and
effects of both T cells and monocytes on growth of hematopoietic
progenitors
L Levitt, TJ Kipps, EG Engleman and PL Greenberg
The efficacy of four separate methods of human bone marrow T lymphocyte
depletion was assessed, and the effect of T cells and monocytes on in vitro
growth of marrow (CFU-GEMM, BFU-E, and CFU-GM) and peripheral blood (BFU-E)
hematopoietic progenitors was determined. Extent of T cell depletion was
assessed by multiparameter fluorescent cell sorter (FACS) analysis and by
functional studies. Cells staining positively by FACS analysis for one or
more of three separate fluorescent pan-T cell monoclonal antibodies (MCAbs)
comprised 8.4% to 9.5% of control marrow mononuclear cells (MNCs). T cells
constituted 3.2% to 5.1% of marrow following single, sequential, or
combination treatment with two different pan-T cell MCAbs (Leu 1 and TM1)
plus complement, 1.5% to 2.2% of marrow following solid-phase
immunoabsorption ("panning"), 0.2% of marrow after sheep cell rosetting,
and only 0.05% of marrow after FACS selective cell sorting and gated
separation. T cells made up 59% to 73% of control peripheral blood MNCs and
0.8% to 2.8% of peripheral MNCs following sheep cell rosetting plus
treatment with Leu 1 MCAb and complement. Mitogen (PHA, Con A) and
allogeneic MLC-induced blastogenic responses (stimulation indices,
experimental/control or E/C) revealed a concordant decrement in marrow T
cell function after MCAb plus complement (E/C of 3.9 to 9.0), after panning
(E/C of 1.6 to 3.5) and after sheep cell rosetting (E/C of 0.7 to 1.3),
compared with control marrow (E/C of 5.3 to 15.7). After T cell depletion,
marrow BFU-E growth was 95% to 120% of control, CFU-GM growth was 90% to
108% of control, and CFU-GEMM growth was 89% to 111% of control. Marrow T
cell and/or monocyte depletion did not alter erythropoietin-dependent BFU-E
growth in the absence of Mo-conditioned medium (81% to 95% of control), and
the addition of as many as 50 to 100 X 10(3) purified marrow monocytes or T
cells to 10(5) autologous nonadherent T cell-depleted marrow target cells
had a negligible (P greater than .1) effect on marrow BFU-E growth in
vitro. Peripheral blood (PB) BFU-E/10(5) T- depleted target cells were 106%
+/- 19% of expected; PB BFU-E growth was significantly diminished after
monocyte depletion alone (7% +/- 6% of expected) or after monocyte plus T
cell depletion (8% +/- 4% of expected).(ABSTRACT TRUNCATED AT 400 WORDS)
Volume 65,
Issue 3,
pp. 663-679,
03/01/1985
Copyright © 1985 by The American Society of Hematology
