Abstract
The bcl-2 gene encodes an intracellular, membrane-associated protein that protects immature cortical thymocytes from a wide variety of apoptotic stimuli, including glucocorticoids, radiation, and anti-CD3 treatment. Since cortical thymocytes are the primary target cells for thymic positive and negative selection processes, and since these processes are associated with cell death, we evaluated the role of bcl- 2 in T cell development in two ways. In the first approach, transgenic mice expressing high levels of Bcl-2 in cortical thymocytes were mated with H-Y T cell receptor (TCR) transgenic mice, the latter being a well- defined system for the study of positive and negative selection of T cells. We found that the bcl-2 transgene had a dramatic effect on positive selection. This was manifested by a greatly increased production of mature thymocytes that were highly skewed towards the CD4- 8+ lineage. The change involving CD4-8+ thymocytes occurred not only in bcl-2 transgenic mice, but was also observed in H-Y TCR/bcl-2 doubly transgenic mice, regardless of whether the H-Y TCR was expressed in the selecting (H-2b) or nonselecting (H-2d) environments. Furthermore, a large proportion of CD4-8+ thymocytes produced in H-2b H-Y TCR/bcl-2 doubly transgenic female mice expressed endogenous TCR alpha chains rather than the transgenic TCR alpha chain. These observations are consistent with the model that high expression of Bcl-2 in cortical thymocytes overrides the normal apoptotic pathway. This then allows the selection of CD4-8+ thymocytes expressing TCRs that are otherwise nonselectable. However, the bcl-2 transgene did not protect CD4+8+ thymocytes expressing the male-specific TCR from deletion in male doubly transgenic mice. In the second approach, we determined the level of bcl-2 mRNA expression in populations of thymocytes defined by their CD4/CD8 phenotypes using quantitative reversed transcriptase PCR techniques. Our results indicate that bcl-2 mRNA was expressed at a high level in immature CD4-8- thymocytes and in mature CD4+8- thymocytes. There is a dramatic downregulation of bcl-2 mRNA in CD4+8+ thymocytes, particularly those expressing a low level of TCR. CD4+8+ thymocytes that upregulated their TCR, likely as a result of receiving positive selection signals, also upregulated bcl-2 mRNA. This observation suggests that rescue of immature thymocytes from the programmed cell death pathway by positive selection signals is accompanied by the upregulation of bcl-2 mRNA.
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- Alnemri E. S., Robertson N. M., Fernandes T. F., Croce C. M., Litwack G. Overexpressed full-length human BCL2 extends the survival of baculovirus-infected Sf9 insect cells. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7295–7299. doi: 10.1073/pnas.89.16.7295. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bakhshi A., Jensen J. P., Goldman P., Wright J. J., McBride O. W., Epstein A. L., Korsmeyer S. J. Cloning the chromosomal breakpoint of t(14;18) human lymphomas: clustering around JH on chromosome 14 and near a transcriptional unit on 18. Cell. 1985 Jul;41(3):899–906. doi: 10.1016/s0092-8674(85)80070-2. [DOI] [PubMed] [Google Scholar]
- Borgulya P., Kishi H., Müller U., Kirberg J., von Boehmer H. Development of the CD4 and CD8 lineage of T cells: instruction versus selection. EMBO J. 1991 Apr;10(4):913–918. doi: 10.1002/j.1460-2075.1991.tb08024.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Borgulya P., Kishi H., Uematsu Y., von Boehmer H. Exclusion and inclusion of alpha and beta T cell receptor alleles. Cell. 1992 May 1;69(3):529–537. doi: 10.1016/0092-8674(92)90453-j. [DOI] [PubMed] [Google Scholar]
- Brändle D., Müller C., Rülicke T., Hengartner H., Pircher H. Engagement of the T-cell receptor during positive selection in the thymus down-regulates RAG-1 expression. Proc Natl Acad Sci U S A. 1992 Oct 15;89(20):9529–9533. doi: 10.1073/pnas.89.20.9529. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carlow D. A., van Oers N. S., Teh S. J., Teh H. S. Deletion of antigen-specific immature thymocytes by dendritic cells requires LFA-1/ICAM interactions. J Immunol. 1992 Mar 15;148(6):1595–1603. [PubMed] [Google Scholar]
- Chen-Levy Z., Nourse J., Cleary M. L. The bcl-2 candidate proto-oncogene product is a 24-kilodalton integral-membrane protein highly expressed in lymphoid cell lines and lymphomas carrying the t(14;18) translocation. Mol Cell Biol. 1989 Feb;9(2):701–710. doi: 10.1128/mcb.9.2.701. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
- Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
- Gratiot-Deans J., Ding L., Turka L. A., Nuñez G. bcl-2 proto-oncogene expression during human T cell development. Evidence for biphasic regulation. J Immunol. 1993 Jul 1;151(1):83–91. [PubMed] [Google Scholar]
- Guidos C. J., Danska J. S., Fathman C. G., Weissman I. L. T cell receptor-mediated negative selection of autoreactive T lymphocyte precursors occurs after commitment to the CD4 or CD8 lineages. J Exp Med. 1990 Sep 1;172(3):835–845. doi: 10.1084/jem.172.3.835. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Herman A., Kappler J. W., Marrack P., Pullen A. M. Superantigens: mechanism of T-cell stimulation and role in immune responses. Annu Rev Immunol. 1991;9:745–772. doi: 10.1146/annurev.iy.09.040191.003525. [DOI] [PubMed] [Google Scholar]
- Hockenbery D. M., Zutter M., Hickey W., Nahm M., Korsmeyer S. J. BCL2 protein is topographically restricted in tissues characterized by apoptotic cell death. Proc Natl Acad Sci U S A. 1991 Aug 15;88(16):6961–6965. doi: 10.1073/pnas.88.16.6961. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hockenbery D., Nuñez G., Milliman C., Schreiber R. D., Korsmeyer S. J. Bcl-2 is an inner mitochondrial membrane protein that blocks programmed cell death. Nature. 1990 Nov 22;348(6299):334–336. doi: 10.1038/348334a0. [DOI] [PubMed] [Google Scholar]
- Huesmann M., Scott B., Kisielow P., von Boehmer H. Kinetics and efficacy of positive selection in the thymus of normal and T cell receptor transgenic mice. Cell. 1991 Aug 9;66(3):533–540. doi: 10.1016/0092-8674(81)90016-7. [DOI] [PubMed] [Google Scholar]
- Jacobs H., Von Boehmer H., Melief C. J., Berns A. Mutations in the major histocompatibility complex class I antigen-presenting groove affect both negative and positive selection of T cells. Eur J Immunol. 1990 Oct;20(10):2333–2337. doi: 10.1002/eji.1830201024. [DOI] [PubMed] [Google Scholar]
- Jorgensen J. L., Reay P. A., Ehrich E. W., Davis M. M. Molecular components of T-cell recognition. Annu Rev Immunol. 1992;10:835–873. doi: 10.1146/annurev.iy.10.040192.004155. [DOI] [PubMed] [Google Scholar]
- Killeen N., Moriarty A., Teh H. S., Littman D. R. Requirement for CD8-major histocompatibility complex class I interaction in positive and negative selection of developing T cells. J Exp Med. 1992 Jul 1;176(1):89–97. doi: 10.1084/jem.176.1.89. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kisielow P., Blüthmann H., Staerz U. D., Steinmetz M., von Boehmer H. Tolerance in T-cell-receptor transgenic mice involves deletion of nonmature CD4+8+ thymocytes. Nature. 1988 Jun 23;333(6175):742–746. doi: 10.1038/333742a0. [DOI] [PubMed] [Google Scholar]
- Kisielow P., Teh H. S., Blüthmann H., von Boehmer H. Positive selection of antigen-specific T cells in thymus by restricting MHC molecules. Nature. 1988 Oct 20;335(6192):730–733. doi: 10.1038/335730a0. [DOI] [PubMed] [Google Scholar]
- Lee N. A., Loh D. Y., Lacy E. CD8 surface levels alter the fate of alpha/beta T cell receptor-expressing thymocytes in transgenic mice. J Exp Med. 1992 Apr 1;175(4):1013–1025. doi: 10.1084/jem.175.4.1013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McDonnell T. J., Nunez G., Platt F. M., Hockenberry D., London L., McKearn J. P., Korsmeyer S. J. Deregulated Bcl-2-immunoglobulin transgene expands a resting but responsive immunoglobulin M and D-expressing B-cell population. Mol Cell Biol. 1990 May;10(5):1901–1907. doi: 10.1128/mcb.10.5.1901. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Montgomery R. A., Dallman M. J. Analysis of cytokine gene expression during fetal thymic ontogeny using the polymerase chain reaction. J Immunol. 1991 Jul 15;147(2):554–560. [PubMed] [Google Scholar]
- Murphy K. M., Heimberger A. B., Loh D. Y. Induction by antigen of intrathymic apoptosis of CD4+CD8+TCRlo thymocytes in vivo. Science. 1990 Dec 21;250(4988):1720–1723. doi: 10.1126/science.2125367. [DOI] [PubMed] [Google Scholar]
- Nakayama K., Nakayama K., Negishi I., Kuida K., Shinkai Y., Louie M. C., Fields L. E., Lucas P. J., Stewart V., Alt F. W. Disappearance of the lymphoid system in Bcl-2 homozygous mutant chimeric mice. Science. 1993 Sep 17;261(5128):1584–1588. doi: 10.1126/science.8372353. [DOI] [PubMed] [Google Scholar]
- Robey E. A., Ramsdell F., Kioussis D., Sha W., Loh D., Axel R., Fowlkes B. J. The level of CD8 expression can determine the outcome of thymic selection. Cell. 1992 Jun 26;69(7):1089–1096. doi: 10.1016/0092-8674(92)90631-l. [DOI] [PubMed] [Google Scholar]
- Rocha B., von Boehmer H. Peripheral selection of the T cell repertoire. Science. 1991 Mar 8;251(4998):1225–1228. doi: 10.1126/science.1900951. [DOI] [PubMed] [Google Scholar]
- Sentman C. L., Shutter J. R., Hockenbery D., Kanagawa O., Korsmeyer S. J. bcl-2 inhibits multiple forms of apoptosis but not negative selection in thymocytes. Cell. 1991 Nov 29;67(5):879–888. doi: 10.1016/0092-8674(91)90361-2. [DOI] [PubMed] [Google Scholar]
- Siegel R. M., Katsumata M., Miyashita T., Louie D. C., Greene M. I., Reed J. C. Inhibition of thymocyte apoptosis and negative antigenic selection in bcl-2 transgenic mice. Proc Natl Acad Sci U S A. 1992 Aug 1;89(15):7003–7007. doi: 10.1073/pnas.89.15.7003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Staerz U. D., Rammensee H. G., Benedetto J. D., Bevan M. J. Characterization of a murine monoclonal antibody specific for an allotypic determinant on T cell antigen receptor. J Immunol. 1985 Jun;134(6):3994–4000. [PubMed] [Google Scholar]
- Strasser A., Harris A. W., Cory S. bcl-2 transgene inhibits T cell death and perturbs thymic self-censorship. Cell. 1991 Nov 29;67(5):889–899. doi: 10.1016/0092-8674(91)90362-3. [DOI] [PubMed] [Google Scholar]
- Strasser A., Harris A. W., Vaux D. L., Webb E., Bath M. L., Adams J. M., Cory S. Abnormalities of the immune system induced by dysregulated bcl-2 expression in transgenic mice. Curr Top Microbiol Immunol. 1990;166:175–181. doi: 10.1007/978-3-642-75889-8_22. [DOI] [PubMed] [Google Scholar]
- Strasser A., Whittingham S., Vaux D. L., Bath M. L., Adams J. M., Cory S., Harris A. W. Enforced BCL2 expression in B-lymphoid cells prolongs antibody responses and elicits autoimmune disease. Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8661–8665. doi: 10.1073/pnas.88.19.8661. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Swat W., Ignatowicz L., von Boehmer H., Kisielow P. Clonal deletion of immature CD4+8+ thymocytes in suspension culture by extrathymic antigen-presenting cells. Nature. 1991 May 9;351(6322):150–153. doi: 10.1038/351150a0. [DOI] [PubMed] [Google Scholar]
- Teh H. S., Kishi H., Scott B., Borgulya P., von Boehmer H., Kisielow P. Early deletion and late positive selection of T cells expressing a male-specific receptor in T-cell receptor transgenic mice. Dev Immunol. 1990;1(1):1–10. doi: 10.1155/1990/18208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Teh H. S., Kishi H., Scott B., Von Boehmer H. Deletion of autospecific T cells in T cell receptor (TCR) transgenic mice spares cells with normal TCR levels and low levels of CD8 molecules. J Exp Med. 1989 Mar 1;169(3):795–806. doi: 10.1084/jem.169.3.795. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Teh H. S., Kisielow P., Scott B., Kishi H., Uematsu Y., Blüthmann H., von Boehmer H. Thymic major histocompatibility complex antigens and the alpha beta T-cell receptor determine the CD4/CD8 phenotype of T cells. Nature. 1988 Sep 15;335(6187):229–233. doi: 10.1038/335229a0. [DOI] [PubMed] [Google Scholar]
- Tsujimoto Y., Finger L. R., Yunis J., Nowell P. C., Croce C. M. Cloning of the chromosome breakpoint of neoplastic B cells with the t(14;18) chromosome translocation. Science. 1984 Nov 30;226(4678):1097–1099. doi: 10.1126/science.6093263. [DOI] [PubMed] [Google Scholar]
- Turner J. M., Brodsky M. H., Irving B. A., Levin S. D., Perlmutter R. M., Littman D. R. Interaction of the unique N-terminal region of tyrosine kinase p56lck with cytoplasmic domains of CD4 and CD8 is mediated by cysteine motifs. Cell. 1990 Mar 9;60(5):755–765. doi: 10.1016/0092-8674(90)90090-2. [DOI] [PubMed] [Google Scholar]
- Vaux D. L., Cory S., Adams J. M. Bcl-2 gene promotes haemopoietic cell survival and cooperates with c-myc to immortalize pre-B cells. Nature. 1988 Sep 29;335(6189):440–442. doi: 10.1038/335440a0. [DOI] [PubMed] [Google Scholar]
- von Boehmer H. Developmental biology of T cells in T cell-receptor transgenic mice. Annu Rev Immunol. 1990;8:531–556. doi: 10.1146/annurev.iy.08.040190.002531. [DOI] [PubMed] [Google Scholar]