IL-4 is a differentiation factor for transforming growth factor-β secreting Th3 cells and oral administration of IL-4 enhances oral tolerance in experimental allergic encephalomyelitis

Abstract

We have previously shown that following oral administration of myelin basic protein (MBP), regulatory T cells are generated from gut-associated lymphoid tissue and that these cells suppress experimental allergic encephalomyelitis (EAE). These regulatory T cells produce transforming growth factor-beta (TGF-beta) with various amounts of IL-4 and IL-10 and these TGF-beta-secreting T cells have been termed Th3 cells. T cells in lymphoid organs drained by mucosal sites secrete IL-4 as a primary T cell growth factor. In the present study, we examined the role of IL-4 on oral tolerance and in the generation of TGF-beta secreting cells. Treatment of (PLJ x SJL)F1 mice with intraperitoneal (i. p.) IL-4 and low-dose oral MBP (0.5 mg) given three times reduced the severity of EAE, whereas i.p. injection of IL-4 alone or oral MBP alone given in these suboptimal doses, showed no protection. Spleen cells from protected mice produced increased amounts of TGF-beta and reduced IFN-gamma upon stimulation with MBP in vitro. Mucosal MBP-specific IgA production was significantly increased in IL-4 plus MBP fed animals. Moreover, oral administration of IL-4 (1 microg per feeding) also enhanced the suppression of EAE by oral MBP and this protective effect was reversed by administration of anti-TGF-beta antibody in vivo. Reverse transcription-PCR showed enhanced suppression of IFN-gamma in Peyer's patch in animals fed MBP and IL-4 versus those fed MBP alone. We then investigated the role of IL-4 in the generation of TGF-beta-secreting cells using MBP Ac1-11 TCR transgenic animals. Cells were cultured with IL-2, IL-4, or IFN-gamma in the presence of MBP and limiting dilution analysis for cytokine-secreting cells performed. We found that IL-4, but not IL-2 or IFN-gamma, generated TGF-beta-secreting T cells from naive splenic T cells and that these cells provided help for IgA production. These findings demonstrate that IL-4 is a differentiation factor for TGF-beta-secreting Th3 cells and oral IL-4 has a synergistic effect on low-dose oral tolerance that is associated with increased TGF-beta secretion.

NK T Cell-Derived IL-10 Is Essential for the Differentiation of Antigen-Specific T Regulatory Cells in Systemic Tolerance

“…Here, we show that during the induction of systemic tolerance after Ag inoculation into the eye, IL-10 mRNA and protein is selectively up-regulated and is absolutely required for the development of active suppression. Thus, although IL-4 is the cytokine usually associated with down-regulation of inflammation (66) and induction of Th3 Tr cells in oral tolerance (67), during the development of eye-induced active suppression, NK T-derived IL-10 is the major player.…”

Mucosal Administration of Heat Shock Protein-65 Decreases Atherosclerosis and Inflammation in Aortic Arch of Low-Density Lipoprotein Receptor-Deficient Mice

“…For immunohistochemistry, cryostat sections (5 m) of the aortic arch were cut, air-dried, fixed in acetone, and stained with anti-MAC-3 for macrophages, anti-CD4 for T cells, and anti-IL-10 (Pharmingen), anti-IFN-␥, and anti-TGF-␤ (R&D) for cytokine staining, as described. 15 Areas that stained positively for macrophages were measured by use of computer-assisted image quantification (IPLAB Spectrum P, 3.1). Lymphocytes identified by anti-CD4 or anti-cytokine antibody staining were counted microscopically by 4 observers blinded to the study protocol.…”

Strategies of mucosal immunotherapy for allergic diseases

“…30,31 High doses of oral or mucosal antigen lead to T cell receptor activation without costimulation and the simultaneous presence of inhibitory ligands leads to anergy 32 or deletion. 16,33 Low-dose tolerance is induced by regulatory cells, such as Th3, 18,19 T regulatory 1 cells 34,35 and CD4 1 CD25 1 regulatory cells. 36,37 Also, CD8 1 T cells, via the production of TGF-b, 38,39 and c/d T cells 40 have been identified as acting as regulatory cells during oral tolerance induction.…”

“…112 Many animal studies have reported that immune therapy for allergic diseases could be given by oral administration of OVA or purified allergens. [113][114][115] In addition to the adjustment of antigen dose and the frequency of dosing 116 for the mucosal adjuvants, including CTB, CpG ODNs and chitosan as previously mentioned, oral tolerance is enhanced by IL-4, 19 19,116,117 anti-IL-12, 118 TGF-â, 119 Flt-3 ligand 120 and anti-CD40 ligand. 121 Antigen absorption following oral administration is less dangerous in regards to the airways or skin, which suggests that the mouth is likely to be a tolerogenic site.…”

“…The long-term time course for these injections may reduce the efficacy of SCIT treatment, owing to the side effects 18 from accompanying potent Th2 adjuvants. 19,20 The possibility of local or systemic adverse effects (such as anaphylaxis) must be considered. The review of SCIT trials 21 found that immunotherapy could reduce asthma symptoms, the need for medications and the risk of severe asthma attacks after future exposure to the allergen.…”