Regulatory T cells limit induction of protective immunity and promote immune pathology following intestinal helminth infection.

TitleRegulatory T cells limit induction of protective immunity and promote immune pathology following intestinal helminth infection.
Publication TypeJournal Article
Year of Publication2014
AuthorsSawant DV, Gravano DM, Vogel P, Giacomin P, Artis D, Vignali DAA
JournalJ Immunol
Volume192
Issue6
Pagination2904-12
Date Published2014 Mar 15
ISSN1550-6606
KeywordsAdaptive Immunity, Animals, Antibodies, Helminth, CD4-Positive T-Lymphocytes, Cytokines, Diphtheria Toxin, Enzyme-Linked Immunosorbent Assay, Flow Cytometry, Forkhead Transcription Factors, Immunoglobulin G, Interferon-gamma, Interleukin-4, Intestines, Mice, Mice, Inbred C57BL, Mice, Transgenic, T-Lymphocytes, Regulatory, Th1 Cells, Th2 Cells, Time Factors, Trichuriasis, Trichuris
Abstract

Foxp3(+) regulatory T cells (Tregs) have a well-characterized role in limiting autoimmunity and dampening deleterious immune responses. However, a potential consequence of the immunosuppressive function of Tregs can be the limitation of protective immunity to infectious pathogens. Parasitic infections are a potent stimulus for the generation of Treg responses, which may be beneficial to both the parasite and the host by promoting persistence of infection and limiting immune-mediated pathology, respectively. In this study, we explore the functional role of Tregs post-low-dose infection with the intestinal helminth parasite Trichuris muris, which yields a chronic infection because of inefficient induction of Th2 responses. Early Treg depletion postinfection resulted in expedited worm clearance, and was associated with reduced Th1-mediated inflammation of the intestinal environment. Interestingly, this protective immunity was lost, and worm burden enhanced if Tregs were depleted later once the infection was established. Early and late Treg depletion resulted in enhanced Th2 and reduced Th1 cytokine and humoral responses. Blockade of the Th2 cytokine IL-4 resulted in a moderate increase in Th1 but had no effect on worm burden. Our findings suggest that Tregs preferentially limit Th2 cell expansion, which can impact infections where clear immune polarity has not been established. Thus, the impact of Treg depletion is context and time dependent, and can be beneficial to the host in situations where Th1 responses should be limited in favor of Th2 responses.

DOI10.4049/jimmunol.1202502
Alternate JournalJ. Immunol.
PubMed ID24532574
PubMed Central IDPMC3955731
Grant ListCA21765 / CA / NCI NIH HHS / United States
P30 CA021765 / CA / NCI NIH HHS / United States
R01 AI091977 / AI / NIAID NIH HHS / United States
R01 AI091977 / AI / NIAID NIH HHS / United States