Expansion of Foxp3+ Regulatory T Cells in Mice Infected with the Filarial Parasite Brugia malayi This information is current as Henry J. McSorley, Yvonne M. Harcus, Janice Murray, of October 2, 2021. Matthew D. Taylor and Rick M. Maizels J Immunol 2008; 181:6456-6466; ; doi: 10.4049/jimmunol.181.9.6456 http://www.jimmunol.org/content/181/9/6456 Downloaded from References This article cites 74 articles, 33 of which you can access for free at: http://www.jimmunol.org/content/181/9/6456.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 *average by guest on October 2, 2021 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 © 2008 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Expansion of Foxp3؉ Regulatory T Cells in Mice Infected with the Filarial Parasite Brugia malayi1 Henry J. McSorley, Yvonne M. Harcus, Janice Murray, Matthew D. Taylor, and Rick M. Maizels2 Many helminths, including Brugia malayi, are able to establish long-lived infections in immunocompetent hosts. Growing evidence suggests that the immune system’s failure to eliminate parasites is at least partially due to the effects of regulatory T cells (Tregs). To test whether parasites may directly stimulate host regulatory activity, we infected mice with two key stages of B. malayi. Both mosquito-borne infective larvae and mature adults i.p. introduced were found to preferentially expand the proportion of ,CD25؉Foxp3؉ cells within the CD4؉ T cell population. The induction of Foxp3 was accompanied by raised CD25, CD103 and CTLA-4 expression, and was shown to be an active process, which accompanied the introduction of live, but not dead parasites. CTLA-4 expression was also markedly higher on Foxp3؊ cells, suggesting anergized effector populations. Peritoneal Downloaded from lavage CD4؉CD25؉ cells from infected mice showed similar suppressive activity in vitro to normal splenic “natural” Tregs. Both B. malayi larvae and adults were also able to induce Foxp3 expression in adoptively transferred DO11.10 T cells, demonstrating that filarial infection can influence the development of T cells specific to a third party Ag. In addition, we showed that induction was intact in IL-4R-deficient animals, in the absence of a Th2 or alternatively activated macrophage response. We conclude that filarial infections significantly skew the balance of the host immune system toward Treg expansion and activation, in a manner dependent on live parasites but independent of a concomitant Th2 response. The Journal of Immunology, 2008, 181: 6456–6466. http://www.jimmunol.org/ uman filarial parasites such as Brugia malayi establish autoimmunity to infectious diseases (14–16). It is an attractive, but long-term, stable infections, causing lymphatic filariasis unproven hypothesis that human filarial infections activate the H and onchocerciasis in over 150 million people world- Treg pathway (17–20). Evidence that Tregs may be involved in wide (1, 2). Lymphatic filariasis covers a spectrum of disease down-modulating human responses to filarial infection stemmed states from asymptomatic carrier (microfilaremic) to chronic lym- originally from the prominence of IL-10 in hyporesponsive micro- phatic dysfunction and elephantiasis (3, 4). Notably, the asymp- filaraemic carriers (21), and the ability of anti-IL-10 and anti- tomatic subjects, who carry high levels of circulating transmission- TGF-␤ to restore the Ag-specific proliferative response in these stage microfilariae, display a muted immunological response (5– individuals (17, 22). More recently, the isolation of Ag-specific by guest on October 2, 2021 8), failing to mount parasite-specific T cell proliferative and Tr1 clones from a microfilaraemic patient (17, 23), and a study cytokine responses. The degree of suppression is accentuated with demonstrating generalized elevation of Treg-associated gene tran- higher parasite loads (9), and can be reversed by anti-filarial che- scription in filarial patients (13), have lent further support to this motherapy (10, 11). Peripheral T cell populations in infected in- interpretation. To date, however, there has been no evidence that dividuals show elevated expression of CTLA-4 and Foxp3, sug- human filarial parasites directly induce or activate the regulatory gesting an increase in effector T cell anergy and regulatory T cell arm of the adaptive immune system. 3 (Treg) activity (12, 13). Taken together, these data indicate an Mouse models of filarial infection have illustrated many parallels active suppression of Ag-specific responses, dependent directly on with human infection (24), and work with natural parasites of rodents the presence of live parasites. ϩ supports the hypothesis that host immunity is compromised by Treg Tregs are a recently recognized subset of CD4 T cells that activity (25–27). In Litomosoides sigmodontis–infected mice, Tregs actively repress immune effector cells in a range of settings from expand in number at the site of infection, whereas the effector popu- lation displays a hyporesponsive Th2 phenotype. Hyporesponsiveness Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, can be broken by depletion of the Tregs using anti-CD25 and co- United Kingdom stimulation of the suppressed Th2 cells using anti-gluco- Received for publication December 13, 2007. Accepted for publication August corticoid-induced TNFR or anti-CTLA-4 (25, 26). In Acanthochei- 22, 2008. lonema viteae, another rodent filarial parasite, an excretory/secretory 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 product known as ES-62 has been shown to have down-regulatory with 18 U.S.C. Section 1734 solely to indicate this fact. effects, including producing a hypoproliferative defect in B and T 1 This work was supported by studentship support from the Medical Research Council cells (28, 29). Finally, in a parasite closely related to B. malayi (B. (to H.J.McS.) and a Research Career Award (to M.D.T). Y.M.H., J.M., and R.M.M. pahangi), restimulation of splenocytes from infected mice expanded a are supported by a Wellcome Trust Programme Grant. ϩ ϩ population of CD25 CTLA-4 cells, with higher expression of 2 Address correspondence and reprint requests to Dr. Rick M. Maizels, Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Lab- mRNA for the Treg master transcription factor, Foxp3 (30). oratories, West Mains Road, Edinburgh EH9 3JT, U.K. E-mail address: Although B. malayi cannot complete its life cycle in immuno- [email protected] competent laboratory mice (31–33), its short-term survival in ro- 3 Abbreviations used in this paper: BMDC, bone marrow-derived dendritic cell; Treg, dents offers the opportunity to study the initial response to a major regulatory T cell. human pathogen. In most mouse strains, the mosquito-borne third- Copyright © 2008 by The American Association of Immunologists, Inc. 0022-1767/08/$2.00 stage infective larvae (L3) will survive for 1–3 wk, whereas adult www.jimmunol.org The Journal of Immunology 6457 A Live L3 B Medium i.p. B. malayi Foxp3+ % of CD4+ lymphocytes CD4+Foxp3+ cell numbers *** *** 105 85.0 15.0 105 70.3 29.7 *** *** 30 100000 104 104 20 N.S. 103 103 50000 CD4 % of CD4+ <Alexa 700-A>: CD4 <Alexa 700-A>: CD4 2 2 10 Cell Numbers 10 10 0 0 0 0 0102 103 104 105 0102 103 104 105 Medium Dead L3 Live L3 Medium Dead L3 Live L3 <APC-A>: FoxP3 <APC-A>: FoxP3 C CD25 MFI in CD4+Foxp3+ cells D * 4.56 3.22 5.18 12.3 * 105 105 600 104 104 400 103 103 <FITC-A>: CD25 <FITC-A>: CD25 CD25 CD25 MFI 200 102 102 0 0 80.3 11.9 65.1 17.4 Downloaded from 2 3 4 5 2 3 4 5 0 010 10 10 10 010 10 10 10 Medium Dead L3 Live L3 <APC-A>: FoxP3 <APC-A>: FoxP3 E CTLA-4hi % of CD4+Foxp3- F CTLA-4hi MFI in CD4+Foxp3+ 5 5 ** 10 7.0 10 15.2 15000 ** 25 ** ** 20 104 104 10000 15 103 103 http://www.jimmunol.org/ 10 <PE-A>: CTLA-4 <PE-A>: CTLA-4 102 102 CTLA-4 MFI 5000 CTLA-4 5 0 0 % of CD4+Foxp3– 93.0 84.8 0 0102 103 104 105 0102 103 104 105 0 <APC-A>: FoxP3 <APC-A>: FoxP3 Medium Dead L3 Live L3 Medium Dead L3 Live L3 CD103+ % of CD4+Foxp3+ H 105 14.5 105 20.9 G 35 ** ** 4 4 30 10 10 25 by guest on October 2, 2021 103 103 20 <PerCP-A>: CD103 <PerCP-A>: CD103 15 102 102 CD103 10 0 0 85.5 79.1 % of CD4+Foxp3+ 5 0102 103 104 105 0102 103 104 105 0 <APC-A>: FoxP3 <APC-A>: FoxP3 Medium Dead L3 Live L3 Foxp3 FIGURE 1. Expression of Foxp3, CD25, CTLA-4, and CD103 following infection with B. malayi L3. A total of 50 B. malayi L3 larvae, or controls of heat-killed L3 B. malayi, or medium alone, were injected i.p. into BALB/c male mice, and peritoneal lavage cells taken 7 days later.