title: Bcl-2 expression promotes B- but not T-lymphoid development in scid mice.
abstract: Expression of antigen receptors is vital for the development of B and T lymphocytes. In mice with the scid mutation, which are unable to make productive rearrangements of their immunoglobulin and T-cell receptor (TCR) genes, lymphopoiesis aborts at an early stage. The death of the immature lymphocytes by apoptosis is postulated to result from a failure to receive a survival signal induced by receptor engagement. Consistent with this hypothesis, introduction of immunoglobulin or TCR transgenes into scid mice promoted an increase in B- or T-lymphoid cells, respectively. As the protein encoded by the bcl-2 gene can inhibit cell death, we tested whether lymphopoiesis could be rescued in scid mice by crossing in a bcl-2 transgene. Strikingly, the bcl-2/scid mice accumulated almost normal numbers of B-lymphoid cells which lacked surface immunoglobulin but expressed markers of maturity. T-cell development remained blocked. Introducing a TCR transgene enabled bcl-2/scid mice to develop normal numbers of CD4+8+ thymocytes even in the absence of immunological selection, suggesting that T cells become competent to respond to bcl-2 protein only after the TCR complex is displayed at the cell surface.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Strasser
authors.forename: A W
authors.initials: AW
authors.lastname: Harris
authors.forename: L M
authors.initials: LM
authors.lastname: Corcoran
authors.forename: S
authors.initials: S
authors.lastname: Cory
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000166:cytology*; D001483:Base Sequence; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D017931:DNA Primers; D016130:Immunophenotyping; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology*
chemical_list: D000943:Antigens, Differentiation; D017931:DNA Primers; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell