Cutting Edge: CCR4 Mediates Antigen-Primed T Cell Binding to Activated Dendritic Cells Meng-tse Wu, Hui Fang and Sam T. Hwang This information is current as J Immunol 2001; 167:4791-4795; ; of September 27, 2021. doi: 10.4049/jimmunol.167.9.4791 http://www.jimmunol.org/content/167/9/4791

Supplementary http://www.jimmunol.org/content/suppl/2001/10/11/167.9.4791.DC1 Downloaded from Material References This article cites 32 articles, 13 of which you can access for free at: http://www.jimmunol.org/content/167/9/4791.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online.

• Rapid Reviews! 30 days* from submission to initial decision

• No Triage! Every submission reviewed by practicing scientists

• Fast Publication! 4 weeks from acceptance to publication

by guest on September 27, 2021 *average

Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts

The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2001 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. ●

Cutting Edge: CCR4 Mediates Antigen-Primed T Cell Binding to Activated Dendritic Cells

Meng-tse Wu, Hui Fang, and Sam T. Hwang1

DC. In the periphery, activated, Ag-bearing DC may bind to cog- The binding of a T cell to an Ag-laden dendritic cell (DC) is a nate effector memory T cells (mTC). In organ culture, mTC-DC critical step of the acquired immune response. Herein, we ad- conjugates have been observed to emigrate from skin of healthy dress whether a DC-produced can induce the arrest donors (12) and can be found in afferent lymph as well (13). of T cells on DC under dynamic flow conditions. Ag-primed T represent a growing family of chemoattractant pro- Downloaded from cells and a T cell line were observed to rapidly (ϳ0.5 s) bind to teins that bind to G -coupled (pertussis toxin-sensitive) immobilized DC at low shear stress (0.1Ð0.2 dynes/cm2)ina transmembrane receptors (14). It has been shown that activated DC pertussis toxin-sensitive fashion. Quantitatively, Ag-primed T may secrete a variety of chemokines (15), including the CCR4 cells displayed 2- to 3-fold enhanced binding to DC compared ligands: CCL22/-derived chemokine (MDC) (16, 17), with unprimed T cells (p < 0.01). In contrast to naive T cells, and CCL17/thymus and activation-regulated chemokine (TARC) primed T cell arrest was largely inhibited by pertussis toxin, (18, 19). Furthermore, both CCL22 and CCL17 have been shown neutralization of the CC chemokine, macrophage-derived che- to attract Ag-activated (but not naive) T cells in chemotaxis assays http://www.jimmunol.org/ mokine (CCL22), or by desensitization of the CCL22 receptor, in vitro (18, 20). Although integrins appear to be important for T CCR4. Our results demonstrate that DC-derived CCL22 in- cell-DC binding, integrins normally are found in an inactive bind- duces rapid binding of activated T cells under dynamic con- ing state, but can be triggered by chemokines to increase both ditions and that Ag-primed and naive T cells fundamentally affinity and avidity for ligands such as ICAM-1 (21). Therefore, we differ with respect to chemokine-dependent binding to hypothesized that DC-produced chemokines may play critical DC. The Journal of Immunology, 2001, 167: 4791Ð4795. roles in DC-T cell binding. To test this hypothesis, we immobilized DC to the floor of a

parallel plate flow chamber, introduced T cells under low shear by guest on September 27, 2021 cell activation by APCs such as , B cells, stress, and observed the rapid binding of T cells to DC under and dendritic cells (DC)2 is critical to the development of conditions that could distinguish durable, shear-resistant adhesion T the acquired immune response (1). Such activation occurs from transient juxtaposition. In contrast to the binding of naive T (2) through the development of an intricate assembly of adhesion cells to DC, the binding of Ag-primed T cells to DC was sensitive and signaling molecules at the interface of the APC and T cell to pertussis toxin (PTX) and mediated by CCR4. Thus, chemo- termed the “immunological synapse” (3) or supramolecular acti- kine-mediated binding demonstrated by primed T cells may rep- vation cluster (4). In order for the immunological synapse to form, resent a selective mechanism for allowing Ag-bearing APC to the T cell must transition from a migratory to a stationary state. preferentially engage activated (or memory) vs naive T cells. Adhesive interactions between the T cell and DC, in part stimu- lated by engagement of the TCR (5, 6), have been reported to be Materials and Methods mediated by several adhesion molecules and their corresponding Reagents, animals, cell lines receptors, which include LFA-1/ICAM-1,-2, -3, CD2/LFA-3, and Recombinant murine chemokines/ were purchased from Pepro- DC-SIGN/ICAM-3 (7–10). Tech (Rocky Hill, NJ) unless otherwise specified. Anti-murine CCL22, T cells may potentially interact with DC at several distinct sites. CXCL13, and CCL11 Abs (all neutralizing, affinity-purified goat IgG) Naive as well as a central memory subset of T cells (11), both were purchased from R&D Systems (Minneapolis, MN). BALB/c and DO11.10 (OVA peptide 323–339-specific) TCR-trans- characterized by expression of CD62L (L-) and CCR7, re- genic mice on a BALB/c background (22) (The Jackson Laboratory, Bar circulate through lymph nodes (LN) and interact with Ag-bearing Harbor, ME) were used in institutionally approved protocols. The T cell hybridoma cell line, B 9.1, is specific for the MHC II-restricted, immuno- dominant hen egg-white lysozyme (HEL) peptide 103–117 (23). BALB/c bone marrow-derived DC (BMDC) were generated as described (24) and Dermatology Branch, National Cancer Institute, Bethesda, MD 20892 cultured in complete medium with RPMI 1640, 5% FCS, IL-4 (10 ng/ml), Received for publication July 30, 2001. Accepted for publication September 4, 2001. GM-CSF (10 ng/ml), and Flt3 ligand (R&D Systems). BMDC were used The costs of publication of this article were defrayed in part by the payment of page on day 9–12 when Ͼ83% of nonadherent cells expressed CD11c, CD40, charges. This article must therefore be hereby marked advertisement in accordance CD80, CD86, and I-Ad by flow cytometry. BMDC showed a 6-fold re- with 18 U.S.C. Section 1734 solely to indicate this fact. sponse to CCL21 vs PBS in chemotaxis assays and no response to CCL5. 1 Address correspondence and reprint requests to Dr. Sam T. Hwang, Dermatology Real-time quantitative RT-PCR was performed as described (25). Branch, National Cancer Institute, Building 10, Room 12N246, 10 Center Drive, In vivo-enriched OVA-primed T cells were generated by s.c. immuniz- Bethesda, MD 20892-1908. E-mail address: [email protected] ing DO11.10-transgenic mice with OVA peptide 323–339 (200 ␮g per 2 mouse) in CFA. Five to 7 days after the immunization, cells from enlarged Abbreviations used in this paper: DC, dendritic cell; LN, lymph node; BMDC, bone ϩ ϩ marrow-derived DC; mTC, memory T cell; nTC, naive T cell; MDC, macrophage- draining LN were pooled and depleted of CD19 and CD40 cells by derived chemokine; TARC, thymus and activation-regulated chemokine; PTX, per- immunomagnetic bead depletion. Naive OVA-specific T cells were iso- tussis toxin; HEL, hen egg-white lysozyme. lated from LN and spleen of DO11.10 mice by identical depletion methods.

Copyright © 2001 by The American Association of Immunologists 0022-1767/01/$02.00

● 4792 CUTTING EDGE: CCR4-MEDIATED T CELL BINDING TO DC

After selection, the resulting cells were ϳ97% CD3eϩ cells and ϳ82% CD4ϩ cells by flow cytometric analysis.

In vitro flow arrest assay For immobilization of BMDC, a droplet of anti-mouse CD40 (HM40-3, 10 ␮g/ml in 100 ␮l PBS; BD PharMingen, San Diego, CA) was first centrally applied to 35-mm plastic dishes at 4°C overnight and then blocked with PBS/1% BSA for 45 min at 25°C. Day 9–12 BMDC (1 ϫ 106/ml, 100 ␮l for each dish) were then applied to the anti-CD40-coated plates for 2.5 h at 4°C. For quantitative analysis of T cell arrest, B 9.1 cells and T cells were labeled with calcein-AM (Molecular Probes, Eugene, OR) and ex- posed to different reagents as indicated: chemokines (25 ng/ml for 30 min at 37°C), anti-chemokines Abs (ant-CCL11, anti-CCL22, and anti- CXCL13 at 2.5 ␮g/ml for 5 min before flow experiments at 20°C), and PTX (100 ng/ml for2hat37°C; Calbiochem, La Jolla, CA). T cells (1 ϫ 106/ml) were resuspended into a 12-ml syringe and introduced into a par- allel plate flow chamber (Glycotech, Rockville, MD) that was affixed to the dish containing immobilized DC. Flow was adjusted to shear stresses of 0.2 (for B 9.1 cells) and 0.1 dynes/cm2 (for DO11.10-derived T cells). Four min after cells entered the chamber, a series of eight images from randomly 2 selected fields (1.18 mm /field) in different quadrants of the dish were Downloaded from video-captured using a ϫ4 objective under fluorescent illumination. Cal- cein-labeled T cells that arrested on the BMDC layer generated bright, single-cell images and were quantified using NIH Image 1.62 and ex- pressed as the mean number of arrested cells per field Ϯ SD. Statistical significance was calculated using a two-sided, Student’s t test. All exper- iments were performed a minimum of three times with similar results. FIGURE 1. B 9.1 cells bind to activated BMDC under dynamic condi- http://www.jimmunol.org/ Results and Discussion tions. A, Calcein-labeled B 9.1 cells were introduced into a parallel plate We found that the T cell hybridoma line, B 9.1, responded to flow chamber at the indicated shear stress in which activated DC were CCL22 in chemotaxis assays with maximal migration (9-fold over immobilized to the floor of the chamber. Cells bound to DC were quantified as described in Materials and Methods. B, B 9.1 cells were either untreated control) occurring between 25 and 100 ng/ml CCL22 (data not or pretreated with function-blocking anti-CD18 mAb. Anti-CD54 mAb shown). By real-time, quantitative RT-PCR, cultured day 11 was used to pretreat DC for 30 min before the flow assay in addition to BMDC expressed levels of mRNA for CCL22 that were at least anti-CD18 mAb treatment of B 9.1 cells in one condition. 1000-fold greater than for CCL21, CXCL12, CXCL13, and CCL19. CCL3 and CCL5 mRNA were expressed at slightly higher, but comparable, levels to CCL22. Supernatants from acti- by guest on September 27, 2021 vated BMDC were effective in stimulating the chemotactic migra- numbers of B 9.1 cells arrested (data not shown). Pretreatment of tion of B 9.1 cells in vitro, which could be blocked by Ͼ90% with B 9.1 cells with anti-CD18 mAb reduced arrest by ϳ80%, while desensitization of CCR4 in the presence of CCL22. combination treatment of B 9.1 cells with anti-CD18 mAb and DC To determine whether chemokines were involved in the binding with anti-CD54 mAb resulted in Ͼ95% loss of arrest (Fig. 1B). B of T cells and DC, we developed a dynamic, flow chamber-based 9.1 cell arrest was dependent on Golgi-mediated transport because assay to measure and record the interactions of B 9.1 cells with arrest was inhibited by 80% when DC were pretreated with brefel- activated DC. We took advantage of a parallel plate flow chamber din A (data not shown). system in which CD40-expressing DC were immobilized to the The rapidity of adherence of the B 9.1 cells to BMDC suggested surface of a plastic culture dish that was precoated with anti-CD40 that a -mediated process may be involved, a mAbs. B 9.1 cells were then introduced into the narrow confines of hypothesis that was strengthened by the observation that PTX sig- the flow chamber under defined shear stress. Arrest of the B 9.1 nificantly reduced arrest by ϳ90% (Fig. 2A). To determine cells to the BMDC was rapid and occurred in Ͻ0.5 s. Some in- whether B 9.1 adhesion to BMDC was mediated by a chemokine teractions were transient (lasting Ͻ4 s), while others were of or chemokines, we desensitized specific chemokine receptors on B longer duration (Ͼ10 s). As shown in Fig. 1A, many adherent cells 9.1 cells by treating them with saturating concentrations of their were noted at 0.2 dynes/cm2, whereas binding was virtually abol- known chemokine ligands (27, 28). While pretreatment with CCL5 ished at shear stresses of 0.5 dynes/cm2 or above. B 9.1 cells that (RANTES), CXCL10 (IFN-␥-inducible protein-10), and macro- arrested remained attached to DC for as long as 12 min, which was phage inflammatory protein-2 had no significant effect on arrest of the longest period of time for which we followed B 9.1 cell bind- B 9.1 cells (Fig. 2A), ϳ90% of adherence of B 9.1 to BMDC could ing. B 9.1 cell binding to activated, skin-derived migratory DC be blocked by pretreatment with CCL22. CCL17 (TARC), the (26) under identical conditions was quantitatively similar to that other known ligand for CCR4, also blocked B 9.1 cell binding to observed with BMDC, suggesting that B 9.1 cells also bound to BMDC (data not shown). Moreover, neutralizing anti-CCL22, but bona fide DC that were not derived from in vitro-cultured cells. not a species-matched anti-CXCL13, Ab prevented the arrest of B Arrested cells were uniformly distributed across the surface of 9.1 cells (Fig. 2B). Thus, the arrest of the B 9.1 T cells to BMDC the flow plate, suggesting that arrest was not the result of cumu- required CCR4 and one of its ligands, CCL22. lative interactions of cells with DC during the transit time across To determine whether the binding of B 9.1 cells to DC was the plate (data not shown). B 9.1 cells showed no expression of resistant to shear stress or was altered when the DC were pulsed CD40 by flow cytometry and did not arrest on anti- with HEL Ag, we allowed B 9.1 cells to bind to DC that were CD40-immobilized LN B cells, demonstrating that B 9.1 cell bind- either not pulsed or pulsed overnight with HEL protein. Once ing was specific for DC and was not the result of artifactual bind- bound, B 9.1 cells were resistant to detachment from DC by shear ing to anti-CD40 mAb. Immobilization of DC could also be stresses of up to 10 dynes/cm2. Interestingly, there were consis- performed with anti-CD80 or -CD86 mAb without affecting the tently 30–50% more B 9.1 cells bound to pulsed compared with The Journal of Immunology 4793

FIGURE 3. Arrest of primed T cells on immobilized BMDC under dynamic conditions. Ag-primed T cells isolated from OVA-immunized DO11.10 mice were introduced into a parallel plate flow chamber contain- ing immobilized BMDC. In the upper left frame (2.558 s after initiation of

video capture), a white primed T cell (indicated by the large arrow) is Downloaded from approaching an immobilized DC (small arrowhead). At 2.992 s, the primed T cell has just touched the boundary of the DC and by 3.426 s (lower left frame) has stopped forward progression and remains in the same position at 9.566 s (lower right frame).

decreased from 92% expression in naive LN T cells (nTC) to 12% http://www.jimmunol.org/ in Ag-primed T cells. In addition, primed T cells showed a recip- rocal increase in expression of the CD44 activation marker (data not shown). As recorded under real-time conditions,3 primed DO11.10 T cells bound to immobilized BMDC under low shear stress conditions (Fig. 3). We then introduced either primed T cells or nTC into the flow chamber that contained immobilized BMDC that either had or had

not been pulsed with OVA peptide. Naive T cells were able to by guest on September 27, 2021 arrest on BMDC, but, as shown in Fig. 4, A and B, there was 2- to 3-fold greater binding of primed T cells to BMDC. Arrest of primed T cells (but not nTC) could be blocked by the presence of anti-CCL22 neutralizing Abs (Fig. 4A) or by pretreatment of primed T cells with CCL22 (Fig. 4B). As was also observed FIGURE 2. CCL22 is essential for B 9.1 cell arrest on activated BMDC. with B 9.1 cells, primed T cell arrest was ϳ50% greater when A, B 9.1 cells were pretreated with the indicated chemokines or PTX as exposed to Ag-pulsed vs nonpulsed DC. Thus, in contrast with ء described in Materials and Methods before initiation of the flow assay. , nTC, primed T cells bound to BMDC in a manner that was Ͻ ϭ p 0.005 vs untreated (n 8). B, The indicated anti-chemokine Abs were highly sensitive to PTX and dependent on CCL22. Furthermore, added to the buffer containing the B 9.1 cells at 2.5 ␮g/ml just before the binding of primed T cells to DC was enhanced by the introduction of the cells into the flow chamber. C, DC, with and without overnight exposure to HEL, were immobilized to the floor of the flow presence of cognate Ag present on the DC. chamber before the initiation of the flow of B 9.1 at three different con- Ours is the first study to demonstrate that a chemokine mediates centrations (1.0, 0.6, and 0.15 ϫ 106 cells/ml) at a uniform shear stress of the binding of a T cell to a DC. In the periphery, DC-mTC 0.2 dynes/cm2. p ϭ 0.001 for HEL-pulsed vs nonpulsed DC at a washing conjugates may play a role in delayed-type hypersensitivity re- shear stress of 1.5 D (dynes/cm2) with 0.6 ϫ 106 cell/ml flowing into the sponses where DC have been observed juxtaposed to lymphocytes chamber (n ϭ 3). (29). In addition, DC-mTC conjugates from skin can increase productive infection with HIV-1 (12). In the LN, recirculating CD62LϩCCR7ϩ mTC may engage Ag-bearing DC arriving from nonpulsed DC (Fig. 2C). Thus, B 9.1 cells bound to DC in a shear- the periphery, possibly leading to expansion of activated effector dependent manner that was CD18/CD54 dependent. Once bound, mTC (11). In contrast to previous studies of the interaction B 9.1 cells were resistant to detachment by exposure to high shear between DC and T cell in culture that used either liquid cultures stress. Finally, although not Ag dependent, the presence of Ag on (30) or a collagen matrix (31), T cells in our system interacted with the DC increased the number of cells arresting on BMDC. DC under conditions in which tight binding could be distinguished To address whether in vivo-derived T cells would arrest on ac- from juxtaposition. The stringency of our system and the ability to tivated DC in a manner similar to the B 9.1 T cell hybridoma cells, easily quantify adhesive events permitted us to dissect the molec- we used the DO11.10 TCR-transgenic mouse, which predomi- ular mechanisms of binding using pharmacologic agents and nantly expresses a TCR that binds to OVA peptide 323–339 in neutralizing Abs. context with H2 (22). Because Ag-primed, but not naive, T cells There is evidence that another CCR4 ligand, CCL17/TARC, from DO11.10 mice are responsive to CCL22 (18, 20), we acti- may be produced by subsets of DC (20), although TARC mRNA vated DO11.10 T cells by immunizing mice with OVA peptide 323–339 in CFA. Activation was observed as L-selectin (CD62L) 3 The on-line version of this article contains supplemental material. 4794 CUTTING EDGE: CCR4-MEDIATED T CELL BINDING TO DC

FIGURE 4. Arrest of primed T cells on activated BMDC is enhanced by the presence of cognate Ag and is CCL22 dependent. A, Primed T cells (PTC) ␮ and nTC (NTC) in buffer containing the indicated neutralizing anti-chemokine Abs (at 2.5 g/ml) were introduced into the flow chamber containing Downloaded from OVA-pulsed (OVADC) or nonpulsed (DC) immobilized DC under conditions similar to those indicated in Fig. 2. At the end of the arrest assay, arrested cells were quantified as described in Materials and Methods. B, Primed T cells and nTC were pretreated with chemokines as described in Materials and Methods before the start of the arrest assay on OVA-pulsed or nonpulsed DC. n ϭ 8 fields per condition for p value calculations.

was only detectable in 14% of cultured murine BMDC (18). How- 5. Dustin, M. L., and T. A. Springer. 1989. T-cell receptor cross-linking transiently http://www.jimmunol.org/ ever, we cannot exclude the possibility that CCL17 may also play stimulates adhesiveness through LFA-1. Nature 341:619. 6. Dustin, M. L., S. K. Bromley, Z. Kan, D. A. Peterson, and E. R. Unanue. 1997. a similar role under other conditions. Furthermore, we cannot ex- Antigen receptor engagement delivers a stop signal to migrating T lymphocytes. clude that other adhesion mechanisms may play a role in DC-T cell Proc. Natl. Acad. Sci. USA 94:3909. binding under less stringent conditions. Certainly, nTC can interact 7. Springer, T. A., M. L. Dustin, T. K. Kishimoto, and S. D. Marlin. 1987. The lymphocyte function-associated LFA-1, CD2, and LFA-3 molecules: cell adhe- with DC as elegantly demonstrated by Ingulli et al. (32). It is sion receptors of the . Annu. Rev. Immunol. 5:223. possible that DC adhere to naive T cells via other means such as 8. Scheeren, R. A., G. Koopman, S. Van der Baan, C. J. Meijer, and S. T. Pals. 1991. the DC-SIGN/ICAM-3 pathway of adhesion that has been shown Adhesion receptors involved in clustering of blood dendritic cells and T lym- phocytes. Eur. J. Immunol. 21:1101.

to be important for resting, but not activated, T cell binding to DC 9. Vilella, R., J. Mila, F. Lozano, J. Alberola-Ila, L. Places, and J. Vives. 1990. by guest on September 27, 2021 (10). Given the low probability that any naive T cell has the correct Involvement of the CDw50 molecule in allorecognition. Tissue Antigens 36:203. receptor for an Ag presented by DC, the lower binding efficiency 10. Geijtenbeek, T. B., R. Torensma, S. J. van Vliet, G. C. van Duijnhoven, G. J. Adema, Y. van Kooyk, and C. G. Figdor. 2000. Identification of DC-SIGN, may actually facilitate rapid sampling and prevent DC from being a novel dendritic cell-specific ICAM-3 receptor that supports primary immune literally “covered” with noncognate nTC for long periods of time. responses. Cell 100:575. It would be interesting to determine which chemokines, if any, are 11. Sallusto, F., D. Lenig, R. Fo¨rster, M. Lipp, and A. Lanzavecchia. 1999. Two subsets of memory T lymphocytes with distinct homing potentials and effector of critical importance in the binding of nTC to DC. functions. Nature 401:708. The interaction of a DC with a T cell plays a critical role in the 12. Pope, M., M. G. Betjes, N. Romani, H. Hirmand, P. U. Cameron, L. Hoffman, initiation and regulation of the acquired immune response. Al- S. Gezeltzer, G. Schuler, and R. M. Steinman. 1994. Conjugates of dendritic cells and memory T lymphocytes from skin facilitate productive infection with HIV-1. though activated DC produce several chemokines, we find that Cell 78:389. lasting adhesive interaction between Ag-primed T cells and DC 13. Mackay, C. R., W. I. Marston, and L. Dudler. 1990. Naive and memory T cells requires CCL22 and CCR4 in our experimental system. The pres- show distinct pathways of lymphocyte recirculation. J. Exp. Med. 171:801. ence of cognate Ag on the DC appears to strengthen this interac- 14. Rossi, D., and A. Zlotnik. 2000. The biology of chemokines and their receptors. Annu. Rev. Immunol. 18:217. tion, although this is not required for adhesion to take place. Thus, 15. Sallusto, F., B. Palermo, D. Lenig, M. Miettinen, S. Matikainen, I. Julkunen, CCL22 may make it possible for DC to efficiently engage activated R. Forster, R. Burgstahler, M. Lipp, and A. Lanzavecchia. 1999. Distinct patterns (or memory) T cells to enhance (or reactivate) immune responses and kinetics of chemokine production regulate dendritic cell function. Eur. J. Im- munol. 29:1617. with a corresponding increase in effector function. 16. Godiska, R., D. Chantry, C. J. Raport, S. Sozzani, P. Allavena, D. Leviten, A. Mantovani, and P. W. Gray. 1997. Human macrophage derived chemokine (MDC) a novel chemoattractant for monocytes, monocyte derived dendritic cells, Acknowledgments and natural killer cells. J. Exp. Med. 185:1595. We thank Drs. Scott I. Simon and Joost J. Oppenheim for helpful discus- 17. Chang, M., J. McNinch, C. Elias, 3rd, C. L. Manthey, D. Grosshans, T. Meng, sions and comments, Dr. Stephen I. Katz and Dr. Atsushi Sato for provid- T. Boone, and D. P. Andrew. 1997. Molecular cloning and functional character- ing DO11.10 mice, and Erik Gonzalez and David Fitzhugh for technical ization of a novel CC chemokine, stimulated T cell chemotactic protein (STCP-1) assistance. that specifically acts on activated T lymphocytes. J. Biol. Chem. 272:25229. 18. Lieberam, I., and I. Fo¨rster. 1999. The murine ␤-chemokine TARC is expressed by subsets of dendritic cells and attracts primed CD4ϩ T cells. Eur. J. Immunol. References 29:2684. 1. Banchereau, J., and R. M. Steinman. 1998. Dendritic cells and the control of 19. Vulcano, M., C. Albanesi, A. Stoppacciaro, R. Bagnati, G. D’Amico, S. Struyf, immunity. Nature 392:245. P. Transidico, R. Bonecchi, A. Del Prete, P. Allavena, et al. 2001. Dendritic cells 2. Lanzavecchia, A., G. Lezzi, and A. Viola. 1999. From TCR engagement to T cell as a major source of macrophage-derived chemokine/CCL22 in vitro and in vivo. activation: a kinetic view of T cell behavior. Cell 96:1. Eur. J. Immunol. 31:812. 3. Grakoui, A., S. K. Bromley, C. Sumen, M. M. Davis, A. S. Shaw, P. M. Allen, 20. Tang, H. L., and J. G. Cyster. 1999. Chemokine up-regulation and activated T cell and M. L. Dustin. 1999. The immunological synapse: a molecular machine con- attraction by maturing dendritic cells. Science 284:819. trolling T cell activation. Science 285:221. 21. Constantin, G., M. Majeed, C. Giagulli, L. Piccio, J. Y. Kim, E. C. Butcher, and ␤ 4. Monks, C. R., B. A. Freiberg, H. Kupfer, N. Sciaky, and A. Kupfer. 1998. Three- C. Laudanna. 2000. Chemokines trigger immediate 2 integrin affinity and mo- dimensional segregation of supramolecular activation clusters in T cells. Nature bility changes: differential regulation and roles in lymphocyte arrest under flow. 395:82. Immunity 13:759. The Journal of Immunology 4795

22. Murphy, K. M., A. B. Heimberger, and D. Y. Loh. 1990. Induction by antigen of tissue chemokine, 6Ckine, Exodus-2) triggers lymphocyte function-associated intrathymic apoptosis of CD4ϩCD8ϩTCRlo thymocytes in vivo. Science 250: antigen 1-mediated arrest of rolling T lymphocytes in peripheral lymph node high 1720. endothelial venules. J. Exp. Med. 191:61. 23. Cabaniols, J. P., R. Cibotti, P. Kourilsky, K. Kosmatopoulos, and 28. Fitzhugh, D. J., S. Naik, S. W. Caughman, and S. T. Hwang. 2000. Cutting edge: J. M. Kanellopoulos. 1994. Dose-dependent T cell tolerance to an immunodom- CC chemokine receptor-6 (CCR6) is essential for arrest of a subset of memory T inant self peptide. Eur. J. Immunol. 24:1743. cells on activated dermal microvascular endothelial cells under physiologic flow 24. Mayordomo, J. I., T. Zorina, W. J. Storkus, L. Zitvogel, C. Celluzzi, L. D. Falo, conditions in vitro. J. Immunol. 165:6677. C. J. Melief, S. T. Ildstad, W. M. Kast, A. B. Deleo, et al. 1995. Bone marrow- 29. Kaplan, G., A. Nusrat, M. D. Witmer, I. Nath, and Z. A. Cohn. 1987. Distribution derived dendritic cells pulsed with synthetic tumour peptides elicit protective and and turnover of Langerhans cells during delayed immune responses in human therapeutic antitumour immunity. Nat. Med. 1:1297. skin. J. Exp. Med. 165:763. 25. Saeki, H., M. T. Wu, E. Olasz, and S. T. Hwang. 2000. A migratory population 30. Delon, J., N. Bercovici, G. Raposo, R. Liblau, and A. Trautmann. 1998. Antigen- of skin-derived dendritic cells expresses CXCR5, responds to B lymphocyte che- 2ϩ moattractant in vitro, and co-localizes to B cell zones in lymph nodes in vivo. dependent and -independent Ca responses triggered in T cells by dendritic cells Eur. J. Immunol. 30:2808. compared with B cells. J. Exp. Med. 188:1473. 26. Larsen, C. P., R. M. Steinman, M. Witmer-Pack, D. F. Hankins, P. J. Morris, and 31. Gunzer, M., A. Schafer, S. Borgmann, S. Grabbe, K. S. Zanker, E. B. Brocker, J. M. Austyn. 1990. Migration and maturation of Langerhans cells in skin trans- E. Kampgen, and P. Friedl. 2000. Antigen presentation in extracellular matrix: plants and explants. J. Exp. Med. 172:1483. interactions of T cells with dendritic cells are dynamic, short lived, and sequen- 27. Stein, J. V., A. Rot, Y. Luo, M. Narasimhaswamy, H. Nakano, M. D. Gunn, tial. Immunity 13:323. A. Matsuzawa, E. J. Q. M. E. Dorf, and U. H. von Andrian. 2000. The CC 32. Ingulli, E., A. Mondino, A. Khoruts, and M. K. Jenkins. 1997. In vivo detection chemokine thymus-derived chemotactic agent 4 (TCA-4, secondary lymphoid of dendritic cell antigen presentation to CD4ϩ T cells. J. Exp. Med. 185:2133. Downloaded from http://www.jimmunol.org/ by guest on September 27, 2021