Regulation of human peripheral blood erythroid burst-forming unit growth by T lymphocytes and T lymphocyte subpopulations defined by OKT4 and OKT8 monoclonal antibodies.
To reexamine the influence that T lymphocytes have on the regulation of human peripheral blood burst-forming unit (BFU-E) proliferation in the absence of a statistically significant number of monocytes, very low numbers (3 to 10 X 10(3)/mL) of a null cell fraction highly enriched for BFU-E were cultured alone and in the presence of 5 X 10(5) sheep erythrocyte-purified, autologous T lymphocytes in a methylcellulose culture system containing erythropoietin. T lymphocytes consistently enhanced the growth of BFU-E from the null cell fraction, as reflected in both their number and size. Irradiation of T lymphocytes prior to coculture with null cells markedly reduced this enhancement, strongly suggesting that T lymphocytes synthesize erythroid burst-promoting factors (BPA). To determine whether there were functional differences between the two major T lymphocyte populations as defined by OKT4 (T helper/inducer) and OKT8 (T suppressor/cytotoxic) murine monoclonal antibodies to stimulate the growth of BFU-E, both T cell subpopulations were isolated by negative (panning) or positive (fluorescence-activated cell sorting) selection and cocultured with null cells. No statistically significant differences emerged between unseparated, OKT4+ and OKT8+ T lymphocytes in their ability to stimulate the growth of BFU-E. Thus, these studies provide further evidence that T lymphocytes are a major population of BPA-producing cells and further that OKT4+ and OKT8+ T lymphocytes equally elaborate these factors.
Wisniewski
D
D
Strife
A
A
Wachter
M
M
Clarkson
B
B
D000818:Animals; D000911:Antibodies, Monoclonal; D002469:Cell Separation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D004912:Erythrocytes / Q000502:physiology*; D004920:Erythropoiesis / Q000528:radiation effects; D005434:Flow Cytometry; D006801:Humans; D008215:Lymphocytes, Null / Q000502:physiology; D051379:Mice; D013601:T-Lymphocytes / Q000145:classification / Q000502:physiology* / Q000528:radiation effects; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology; D050378:T-Lymphocytes, Regulatory / Q000502:physiology
D000911:Antibodies, Monoclonal