title: Lymphopoiesis and IL-7.
abstract: Interleukin 7 (IL-7) is a cytokine initially referred to as pre-B cell growth factor because of its growth-promoting activity for cells early in the B lymphocyte lineage. Subsequent to IL-7 gene cloning and expression, IL-7 was also found to influence the activity of cells in the T lineage. Some of the effects of IL-7 on B and T lymphocyte behavior, both in vitro and in vivo, are discussed here. The growth of pre-B cells in Whitlock-Witte long-term bone marrow cultures [1] provided the basis for the cloning of IL-7 [2]. Such cultures consist of at least two cellular elements: 1) a stromal cell layer and 2) lymphoid cells growing in clusters around the stromal cells. A cDNA encoding IL-7 was cloned utilizing a direct expression cloning strategy. A transformed stromal cell line was used as a source of RNA from which a cDNA library was constructed, inserted into a mammalian expression vector and expressed in COS 7 cells. The COS cells were then screened for secretion of IL-7 into the culture medium as defined by the ability to support stromal cell-independent growth of the lymphoid elements from long-term Whitlock-Witte cultures. In addition to its effects on cells from long-term marrow cultures, IL-7 stimulates growth of cells in cultures of fresh bone marrow [3]. Cells from whole bone marrow plated in semisolid agar form colonies in the presence of IL-7. If the marrow is first enriched for cells expressing the B220 antigen before culture in IL-7, the plating efficiency is increased dramatically.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Immunex Research and Development Corporation, Seattle, Washington 98101.
authors.forename: M B
authors.initials: MB
authors.lastname: Widmer
authors.forename: P J
authors.initials: PJ
authors.lastname: Morrissey
authors.forename: R G
authors.initials: RG
authors.lastname: Goodwin
authors.forename: K H
authors.initials: KH
authors.lastname: Grabstein
authors.forename: L S
authors.initials: LS
authors.lastname: Park
authors.forename: J D
authors.initials: JD
authors.lastname: Watson
authors.forename: P W
authors.initials: PW
authors.lastname: Kincade
authors.forename: P J
authors.initials: PJ
authors.lastname: Conlon
authors.forename: A E
authors.initials: AE
authors.lastname: Namen
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D003520:Cyclophosphamide / Q000494:pharmacology; D066298:In Vitro Techniques; D015851:Interleukin-7 / Q000502:physiology*; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D015851:Interleukin-7; D003520:Cyclophosphamide