CD24 IN T LYMPHOCYTE HOMEOSTATIC PROLIFERATION AND AUTOIMMUNE DISEASE DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Ou Li, Bachelor of Medicine The Ohio State University 2005 Dissertation Committee: Yang Liu, Ph.D., Advisor Approved By Pan Zheng, M.D., Ph.D. W. James Waldman, Ph.D. _________________________________ Xuefeng Bai, M.D., Ph. D. Advisor Jianxin Gao, M.D., Ph.D. Department of Pathology ABSTRACT In this thesis, we show that CD24 can regulate naïve T cell homeostatic proliferation and autoimmune disease. The activation of T lymphocyte requires two signals from antigen presenting cells, peptide and self-MHC complex to TCR and co stimulatory signals. CD24, a glycosyl-phosphatidylinositol (GPI) arched glycoprotein, is an important co-stimulatory molecule. Although it is not essential for induction of T cell response, CD24 is required to express on T cells and for the induction of experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). Here, we show that CD24 is essential for local clonal expansion and persistence of T cells after their migration into the CNS, and that expression of CD24 on either hematopoietic cells or non-hematopoietic antigen-presenting cells in the recipient is sufficient to confer susceptibility to EAE. At the same time, it is well established that T lymphocytes undergo homeostatic proliferation in lymphopenic environment. The homeostatic proliferation requires recognition of major histocompatibility complex on the host. Recent studies have demonstrated that co-stimulation, mediated by CD28, 4-1BB, and CD40, is not required for T cell homeostatic proliferation. Here, we report that T cells from mice with a targeted mutation of CD24 have a remarkably reduced rate of proliferation when adoptively transferred into syngeneic lymphopenic hosts. The reduced proliferation cannot be attributed to abnormal survival and homing properties of the CD24-deficient T cells. T ii cell proliferation in allogeneic hosts is less affected by this mutation. Thus, although distinct co-stimulatory molecules are involved in antigen-driven proliferation and homeostatic proliferation, both processes can be modulated by co-stimulatory molecules. Surprisingly, in the lymphopenic CD24-deficient mice, T cells launch an uncontrollable proliferation that results in rapid death of the recipient mice. The dividing T cells have the phenotypes similar to those activated by cognate antigens. In addition, the CD24- deficient DC have superior capacity to drive homeostatic proliferation of the syngeneic cells. Thus, our data demonstrate that CD24 expressed on the host antigen-presenting cells limits T cell response to homeostatic cue and prevents fatal damage associated with the uncontrolled homeostatic proliferation. Taken together, in this thesis, we demonstrate that although CD24 is not essential for the induction of T cell response, it can regulate T cell homeostatic proliferation and its function in autoimmune disease. iii Dedicated to Ming iv ACKNOWLEDGMENT Foremost, I would like to thank my advisor, Dr. Yang Liu, for his intellectual support, encouragement and patience over the years. His dedication to research and his working ethic inspired me beyond scientific field. Also, I would like to express my appreciation to all present and past members of Drs. Liu’s and Zheng’s lab for their scientific support and friendship. I truly appreciate their generous assistance that make this dissertation possible: Huiming Zhang, Jian-xin Gao, Ken May, Qunmin Zhou, Yin Wang, Yan Liu, Ergun Kocak, Xing Chang, Xingluo (Tom) Liu, Jing Wen, John Richard, Ping Lu, Penghui Zhou, Lizhong Wang, Runhua Liu, Cindy Wu, Jinqing Liu, Tao Zuo, Yi Xiao, Beth McNally, Ken Lute and Pramod Joshi, Tianyu Yang, Peishuang Du, Lisa Yin and Jennifer Kiel. I am particularly grateful for Lynde Shaw’s friendship and enthusiastic support. I also want to especially thank Dr. Xuefeng Bai for helping me start on the right track in the lab. The data presented in Chapter 2 were obtained by collaboration with Dr. Bai. At the Department of Pathology, I would especially like to thank Dr. James Waldman and Mrs. Gretchen Staschiak, both for organizing the graduate curriculum and for keeping in touch with me all the time to help my Ph.D. works progress very well. I would like to give special thanks to Dr. Peter J. Nielsen for providing CD24 knockout v mice. Moreover, my research works are supported by grants from the National Institute of Health (CA82355, CA69091, CA58033 and AI51342). Finally, I couldn’t be more thankful to my devoted parents, who provide me unconditional love and support. Mostly, I am very grateful to my husband, Ming Jiang, whose love and patient help me through out the years. vi VITA June 7, 1976………………………………………………Born-Changchun, P.R. China 1995-2000 …………………….........................................Bachelor of Medicine, Beijing Medical University 2000-presemt…………………………........Graduate Research Associate, Department of Pathology, The Ohio State University PUBLICATIONS Research Publications: 1. Ou Li, Jin-Qing Liu, Pan Zheng, Yang Liu, and Xue-Feng Bai. L-selectin is required for the induction but not effector function of T cells in the experimental autoimmune encephalomyelitis. Submitted. 2. Ou Li, Pan Zheng, and Yang Liu. CD24 expression on T cells is required for optimal T cell proliferation in lymphopenic host. Journal of Experimental Medicine. 200(8):1083- 1089, 2004. 3. Ou Li, Xue-Feng Bai, Qunmin Zhou, Huiming Zhang, Pramod S. Josh, Xincheng Zheng, Yan Liu, Yin Wang, Pan Zheng, and Yang Liu. CD24 controls expansion and persistence of autoreactive T cells in the central nervous system during experimental autoimmune encephalomyelitis. Journal of Experimental Medicine. 200(4):447-458, 2004. 4. Qunmin Zhou, Kottil Rammohan, Shili Lin, Nikki Robinson, Ou Li, Xingluo Liu, Xue- Feng Bai, Lijie Yin, Bruce Scarberry, Peishuang Du, Ming You, Kunliang Guan, Pan Zheng, and Yang Liu. CD24 is a genetic modifier for risk and progression of multiple sclerosis. Proceedings of the National Academy of Sciences. 100(25):15041-15046, 2003. vii 5. Xingluo Liu, Jian Xin Gao, Jing Wen, Lijie Yin, Ou Li, Tao Zuo, Thomas F. Gajewski, Yang-Xin Fu, Pan Zheng, and Yang Liu. B7DC/PDL2 promotes tumor immunity by a PD-1-independent mechanism. Journal of Experimental Medicine. 197(12):1721-1730, 2003. 6. Xue-Feng Bai, Jin-Qing Liu, Ou Li, Pan Zheng, and Yang Liu. Antigenic drift as a mechanism for tumor evasion of destruction by cytolytic T lymphocytes. Journal of Clinical Investigation. 111(10):1487-1496, 2003. 7. Xue-Feng Bai, Jonathan Bender, Jinqing Liu, Huiming Zhang, Yin Wang, Ou Li, Peishuang Du, Pan Zheng, and Yang Liu. Local costimulation reinvigorates tumor- specific cytolytic T lymphocytes for experimental therapy in mice with large tumor burdens. Journal of Immunology. 167(7):3936-3943, 2001. FIELD OF STUDY Major Field: Pathology viii TABLE OF CONTENTS Page Abstract……………………………………………………………………………….….ii Dedication…………………………………………………………………………….….iv Acknowledgements……………………………………………………………………....v Vita…………………………………………………………………………………........vii List of Tables……………………………………………………………………….........xi List of Figures…………………………………………………………………………..xii Statement…………………………………………………………………………….....xiv Chapters: 1. Introduction……………………………………………..…………………...........1 1.1 T lymphocyte and antigen presentation…………….....1 1.2 CD24……………………………………………………..2 1.3 MS, EAE and CD24………………………………….....4 1.4 T cell homeostatic proliferation……………………......8 2. CD24 controls expansion and persistence of autoreactive T cells in the central nerve system during experimental autoimmune encephalomyelitis…………………………………………………………..12 2.1 Abstract………………………………………………...12 2.2 Introduction…………………………..………………..13 2.3 Material and Methods………………..……………….15 2.4 Results…………………………………..……………...21 ix 2.5 Discussion………………………………..…………….30 3. CD24 expression on T cells is required for optimal T cell proliferation in lymphopenic host………………..…………………………………………59 3.1 Abstract………...………………………………………59 3.2 Introduction……...…………………………………….60 3.3 Material and Methods…...……………………………61 3.4 Results and Discussion……...…………………………63 4. Massive and destructive T-cell response to homeostatic cue in the CD24- deficient lymphopenic hosts……………………...………………………..81 4.1 Abstract………………………...………………………81 4.2 Introduction……………………...…………………….82 4.3 Material and Methods……………..………………….83 4.4 Results………………………………...………………..86 4.5 Discussion……………………………..……………….92 5. Conclusion………………………………………………………………………118 Bibliography………………………………………………………………………123 x LIST of TABLE Table Page Table1. Fetal destruction of T cell proliferation in CD24-/- host……………………....113 xi LIST OF FIGURES Figure Page 2.1 CD24 is required for persistence but not recruitment of autoreactive T cells in the EAE model…………………………………...............................................................36 2.2 Quantitation of T cells in the brain of WT and CD24-/- mice………………...…….38 2.3 CNS infiltration of the MOG-active T cells from Thy1.1 congenic mice……..……41 2.4 Requirement for CD24 for optimal T cell proliferation in the CNS……………..….43 2.5 Antigen-specific T cells undergo apoptosis at similar rates in WT and CD24-/- CNS………………………………………………………………………………..…45 2.6 Cytokine gene expression in brains of WT and CD24-/- mice on day 12 and 29 after adoptive transfer of T cells……………………………………………………….….47 2.7 CD24-/-CNS astrocytes had a reduced capacity to stimulate MOG-specific T