In vitro growth of bone marrow-resident T cell precursors supported by mast cell growth factor and IL-3.
The growth requirements of bone marrow-resident cells that are able to differentiate along the T cell lineage (pre-T cells) have not been well established. We recently have shown that the T cell-derived lymphokine IL-3 is able to maintain pre-T cells in vitro for at least 2 weeks. However, in our initial studies, we were not able to ascertain whether IL-3 induced pre-T cell growth during culture, or whether IL-3 simply maintained the viability of these progenitors. To address this issue, we used a multiple dose assay system to assess the level of pre-T cell activity (thymic repopulation) in a selected population of bone marrow cells (CD3-, Thy-1.2+) both before and after culture in IL-3. In addition, we tested the potential role of mast cell growth factor (MGF) in the growth and maintenance of pre-T cells in vitro. The results of these studies showed that IL-3 produced a modest, but consistent increase in the pre-T cell activity during culture. Culture of CD3-, Thy-1.2+ bone marrow cells in MGF also resulted in an increase in the total amount of detectable pre-T cell activity among the cultured cells. The most dramatic increases in pre-T cell activity, however, were induced by the culture of the selected marrow cells in both MGF and IL-3. Cultures supplemented with both cytokines produced net increases in pre-T cell activity of 40- to 75-fold after 10 days of culture. Because the increases in pre-T cell activity were not accompanied by observable increases in the size of thymic colonies produced by the pre-T cells, the increased levels of pre-T cell activity appeared to result from increases in pre-T cell numbers during culture. Thus, in addition to the other activities ascribed to MGF, this cytokine displays pre-T cell growth factor activity and can synergize with IL-3 in that capacity. The use of MGF in conjunction with IL-3 provides the best system described to date for the propagation of pre-T cells in primary bone marrow cell cultures.
Chervenak
R
R
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130.
Dempsey
D
D
Soloff
R S
RS
Smithson
G
G
D000818:Animals; D001853:Bone Marrow / Q000276:immunology; D001854:Bone Marrow Cells; D016026:Bone Marrow Transplantation; D002469:Cell Separation; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D005434:Flow Cytometry; D016298:Hematopoietic Cell Growth Factors / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D066298:In Vitro Techniques; D007377:Interleukin-3 / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D051379:Mice; D008806:Mice, Inbred AKR; D019089:Stem Cell Factor; D013601:T-Lymphocytes / Q000502:physiology*
D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D019089:Stem Cell Factor