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Immunity. 1994 Jun;1(3):197-205.

Bcl-2 is upregulated at the CD4+ CD8+ stage during positive selection and promotes thymocyte differentiation at several control points.

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Howard Hughes Medical Institute, Department of Medicine and Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.


In vivo thymocyte maturation models were used to investigate the differentiation role of Bcl-2. In alpha/beta T cell receptor (TCR) class II-restricted transgenic mice, Bcl-2 was upregulated at the CD4+ CD8+ stage during positive selection. The lckpr-bcl2 transgene was bred onto MHC classes I-I- and II-I-, MHC-I-, and alpha/beta TCR backgrounds to determine whether Bcl-2 promoted thymocyte maturation in the absence of coreceptor-MHC interaction. Bcl-2 rescued CD8+ thymocytes in class I-I- and alpha/beta TCR in mice; however, they were not exported to the periphery. Bcl-2 had no effect on CD4 lineage maturation in class II-I- mice. No single-positive thymocytes accumulate in MHC-I- mice despite overexpressed Bcl-2. Thus, Bcl-2 enables selection of certain TCRs on class II molecules and their differentiation along the CD8 pathway; however, Bcl-2 did not substitute for positive selection. In RAG-1-I- mice, Bcl-2 promoted differentiation to the CD4+ CD8+ stage. Bcl-2 can promote thymocyte maturation at several control points.

[Indexed for MEDLINE]

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