L-Selectin Is Not Required for T Cell-Mediated Autoimmune Diabetes 1 Randall H. Friedline,* Carmen P. Wong,* Douglas A. Steeber, † Thomas F. Tedder, † and Roland Tisch 2 * Administration of anti-L-selectin (CD62L) mAb to neonatal nonobese diabetic (NOD) mice mediates long term protection against the development of insulitis and overt diabetes. These results suggested that CD62L has a key role in the general function of  cell-specific T cells. To further examine the role of CD62L in the development of type 1 diabetes, NOD mice lacking CD62L were established. The onset and frequency of overt diabetes were equivalent among CD62L / , CD62L / , and CD62L / NOD littermates. Furthermore, patterns of T cell activation, migration, and  cell-specific reactivity were similar in NOD mice of all three genotypes. Adoptive transfer experiments with CD62L / CD4  T cells prepared from BDC2.5 TCR transgenic mice revealed no apparent defects in migration to pancreatic lymph nodes, proliferation in response to  cell Ag, or induction of diabetes in NOD.scid recipients. In conclusion, CD62L expression is not essential for the development of type 1 diabetes in NOD mice. The Journal of Immunology, 2002, 168: 2659 –2666. T ype 1 diabetes (T1D) 3 is characterized by the T cell-me- diated destruction of the insulin-producing  cells of the pancreas. In nonobese diabetic (NOD) mice, a model of spontaneous autoimmune diabetes, disease development proceeds in a regulated and progressive manner (1– 6). Initial islet infiltra- tion (insulitis) involves the recruitment of APCs including macro- phage and dendritic cells (7). These APC are believed to take up  cell Ags, traffic to the pancreatic lymph nodes, and present au- toantigenic peptides to T cells (2, 8). Activation of islet-reactive T cells results in their homing to the pancreas and the initiation of  cell destruction. Infiltration of the pancreas is first detectable at 3– 4 wk of age and progresses over several weeks. When 90% of  cells have been destroyed, normoglycemic regulation is lost, resulting in overt diabetes. Diabetogenesis depends on the effective recruitment of lympho- cytes into pancreatic tissue. In general, lymphocyte trafficking in- volves a cascade of adhesive contacts mediated by membrane- bound adhesion molecules and soluble chemoattractants that induce lymphocyte rolling along the endothelium, firm adhesion to the endothelial wall, and extravasation into tissues (9). The selectin family, consisting of L-, E-, and P-selectin, induces rolling along high endothelial venules of secondary lymphoid organs and in- flamed tissue, thus allowing critical secondary interactions medi- ated by chemokine signaling and integrins to stop cell rolling and promote diapedesis (10, 11). The disruption of L-selectin (CD62L), in particular, has profound effects in vivo, including the severe reduction of lymphocyte migration to peripheral lymph nodes, impaired recruitment of lymphocytes to sites of inflamma- tion, and delayed primary T cell responses (12–15). Several reports support a critical role for CD62L in organ-spe- cific autoimmune diseases. For example, treatment of NOD mice with mAb against CD62L, or one of its ligands, peripheral lymph node addressin (PNAd), blocks the development of Sjo ¨gren’s syn- drome by inhibiting infiltration of the lacrimal and salivary glands (16). Additionally, in a transgenic model of experimental autoim- mune encephalomyelitis (EAE), mice deficient in CD62L (CD62L -/- ) are refractory to demyelination and protected from EAE (17). During the establishment and progression of T1D, PNAd and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) ex- pression are up-regulated in the pancreas. Because both can serve as ligands for CD62L, it suggested that CD62L-mediated interac- tions may be involved in lymphocyte trafficking to the pancreas (18 –20). Indeed, we and others have shown previously that ad- ministration of anti-CD62L mAb to NOD mice can protect against the development of insulitis and diabetes (21, 22). This protection was highly effective when administered to neonatal NOD mice but less so in adults, suggesting that CD62L interactions are important during the establishment of insulitis and  cell-specific T cell responses. In this study, we established NOD mice deficient in CD62L expression to further examine the importance of this selectin in  cell-specific T cell reactivity and the development of T1D. Sur- prisingly, we found that onset and frequency of overt diabetes were equivalent among CD62L +/+ , CD62L +/- , and CD62L -/- NOD littermates. Furthermore, T cell activation, migration, and  cell- specific reactivity were similar among all three genotypes. Finally, the ability of T cells from BDC2.5-transgenic (Tg) TCR mice to migrate into pancreatic lymph nodes, proliferate in response to  cell Ags, and initiate diabetes did not require CD62L expression. *Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599; and † Department of Immunology, Duke University Medical Center, Durham, NC 27710 Received for publication October 9, 2001. Accepted for publication January 9, 2002. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 This work was supported in part by National Institutes of Health Grants R01DK52365 (to R.T.), R01CA54464, and R01CA81776 (to T.F.T.) and National Institute of Allergy and Infectious Diseases Training Grant 5-T32-AI07273 (to R.H.F. and C.P.W). 2 Address correspondence and reprint requests to Dr. Roland Tisch, Department of Microbiology and Immunology, Mary Ellen Jones Building, Room 635, Campus Box 7290, University of North Carolina, Chapel Hill, NC 27599-7290. E-mail address: rmtisch@med.unc.edu 3 Abbreviations used in this paper: T1D, type 1 diabetes; CD62L, L-selectin; EAE, experimental autoimmune encephalomyelitis; GAD65, glutamic acid decarboxylase 65; HSP60, heat shock protein 60; MAdCAM-1, mucosal addressin cell adhesion molecule-1; NOD, nonobese diabetic; PNAd, peripheral lymph node addressin; Tg, transgenic. Copyright © 2002 by The American Association of Immunologists 0022-1767/02/$02.00