Intranasal administration of retinal antigens induces transient T cell activation and apoptosis within drainage lymph nodes but not spleen

Long-term outcome of individuals treated with oral insulin: diabetes prevention trial-type 1 (DPT-1) oral insulin trial

OBJECTIVE

To evaluate the long-term intervention effects of oral insulin on the development of type 1 diabetes and to assess the rate of progression to type 1 diabetes before and after oral insulin treatment was stopped in the Diabetes Prevention Trial-Type 1 (DPT-1).

RESEARCH DESIGN AND METHODS

The follow-up included subjects who participated in the early intervention of oral insulin (1994-2003) to prevent or delay type 1 diabetes. A telephone survey was conducted in 2009 to determine whether diabetes had been diagnosed and, if not, an oral glucose tolerance test (OGTT), hemoglobin A1c (HbA1c), and autoantibody levels were obtained on all subjects who agreed to participate.

RESULTS

Of 372 subjects randomized, 97 developed type 1 diabetes before follow-up; 75% of the remaining 275 subjects were contacted. In the interim, 77 subjects had been diagnosed with type 1 diabetes and 54 of the remainder have had an OGTT; 10 of these were diagnosed with type 1 diabetes, subsequently. Among individuals meeting the original criteria for insulin autoantibodies (IAAs) (≥80 nU/mL), the overall benefit of oral insulin remained significant (P=0.05). However, the hazard rate in this group increased (from 6.4% [95% CI 4.5-9.1] to 10.0% [7.1-14.1]) after cessation of therapy, which approximated the rate of individuals treated with placebo (10.2% [7.1-14.6]).

CONCLUSIONS

Overall, the oral insulin treatment effect in individuals with confirmed IAA≥80 nU/mL appeared to be maintained with additional follow-up; however, once therapy stopped, the rate of developing diabetes in the oral insulin group increased to a rate similar to that in the placebo group.

Chitosan Interferon-gamma Nanogene Therapy for Lung Disease: Modulation of T-Cell and Dendritic Cell Immune Responses

The use of chitosan nanoparticles as carriers for expression plasmids represents a major improvement in gene expression technology. We demonstrated previously that treatment with chitosan interferon-γ (IFN-γ) plasmid deoxyribonucleic acid (DNA) nanoparticles (chitosan interferon-γ nanogene [CIN]) led to in situ production of IFN-γ and a reduction in inflammation and airway reactivity in mice, but the mechanism underlying the immunomodulatory effects of CIN remains unclear. In this report, the effect of CIN treatment on the immune responses of CD8⁺ T cells and dendritic cells was examined in a BALB/c mouse model of ovalbumin (OVA)-induced allergic asthma. OT1 mice (OVA-T cell receptor [TCR] transgenic) were also used to test the effects of CIN on OVA-specific CD8⁺ T cells. CIN treatment caused a reduction in IFN-γ production in a subpopulation of OVA-specific CD8⁺ T cells cultured in vitro in the presence of OVA. CIN also reduced apoptosis of the CD8⁺ T cells. Examination of dendritic cells from lung and lymph nodes indicated that CIN treatment decreased their antigen-presenting activity, as evident from the reduction in CD80 and CD86 expression. Furthermore, CIN treatment significantly decreased the number of CD11c⁺b⁺ dendritic cells in lymph nodes, suggesting that endogenous IFN-γ expression may immunomodulate dendritic cell migration and activation. CIN therapy results in a reduction in proinflammatory CD8⁺ T cells and decreases the number and antigen-presenting activity of dendritic cells.

Mechanisms for inducing nasal mucosal tolerance in experimental autoimmune uveoretinitis

Delivering soluble (auto) antigenic peptides via the naso-respiratory route induces tolerance to that peptide and suppression of experimental models of autoimmune disease. In the normal lung, respiratory tract dendritic cells (RTDCs) efficiently endocytose soluble antigens, migrate to regional lymph nodes and present peptide to T cells that subsequently become tolerant. This article describes protocols for inducing tolerance via the naso-respiratory tract in experimental autoimmune uveoretinitis (EAU); for the isolation of RTDCs to facilitate definition of, and conditions for, maturation and activation of cells; and to test RTDC ability to induce tolerance in murine EAU when adoptively transferred.

Enhanced tolerance to autoimmune uveitis in CD200-deficient mice correlates with a pronounced Th2 switch in response to antigen challenge

A single exposure to inhaled Ag 10 days before immunization leads to long term, Ag-specific tolerance. Respiratory tract myeloid APCs are implicated, but how regulation is invoked, and how tolerance is sustained are unclear. This study examines the in vivo function of the myeloid regulatory molecule CD200 in the process of tolerance induction. Despite earlier onset of experimental autoimmune uveitis in sham-tolerized, CD200-deficient mice, disease incidence and subsequent severity were actually reduced compared with those in wild-type mice. Protection was more effective and long term, lasting at least 28 days. Halting disease progression and tolerance in CD200(-/-) mice correlated with a marked increase in Th2-associated cytokine production by Ag-challenged splenocytes. Reduced overall disease and enhanced tolerance in the CD200-deficient mice in this model system were unexpected and may be related to altered populations of MHC class II(low) APC in the respiratory tract compared with wild-type mice together with associated activation of STAT6 in draining lymph nodes of tolerized mice. These data indicate that in the absence of default inhibitory CD200 receptor signaling, alternative, powerful regulatory mechanisms are invoked. This may represent either permissive dominant Th2 activation or an altered hierarchy of negative signaling by other myeloid cell-expressed regulatory molecules.

Inhibition of experimental autoimmune uveoretinitis by systemic and subconjunctival adenovirus-mediated transfer of the viral IL-10 gene

Pathological ocular manifestations result from a dysregulation in the balance between proinflammatory type 1 cytokines and regulatory type 2 cytokines. Interleukin-10 (IL-10) is an anti-inflammatory cytokine with potent immunosuppressive effects. We have examined the efficiency of viral IL-10 adenovirus (Ad-vIL-10)-mediated gene transfer on experimental autoimmune uveoretinitis (EAU) induced in mice and rats by purified retinal autoantigens, respectively, interphotoreceptor binding protein (IRBP) and S-antigen (S-Ag). B10-A mice that received a single unilateral injection of Ad-vIL-10 in the retro-orbital sinus venosus performed 1 day before immunization with IRBP in the footpads showed high levels of circulating vIL-10 in their sera and a significant reduction in pathological ocular manifestations. Lower levels of IFN-gamma and IL-2 were found in cellular supernatants from IRBP-stimulated splenic cells in these treated mice. The local effect on ocular disease of vIL-10 was neutralized completely by injection of a monoclonal anti-vIL-10 antibody, demonstrating the specificity of the treatment. To determine whether the transfer of the vIL-10 gene within the periocular tissues of the eye could prevent acute EAU, a subconjunctival injection of Ad-vIL-10 was performed in Lewis rats simultaneously with S-antigen in the footpads. This injection determined in situ vIL-10 expression with very low circulating vIL-10 and led to a significant reduction of EAU without affecting the systemic immune response. The present results suggest that Ad-mediated gene transfer resulting in systemic and local expression of vIL-10 provide a promising approach for the treatment of uveitis.

Differential expression of cytokines (IL-2, IFN-gamma, IL-10) and adhesion molecules (VCAM-1, LFA-1, CD44) between spleen and lymph nodes associates with remission in chronic relapsing experimental autoimmune encephalomyelitis

We have recently established chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE) in SJL mice with a modified protocol. In this model, splenectomy aborts the relapsing-remitting course of the disease, and adoptive transfer of lymphocytes of the local draining lymph nodes (LNs) to naive recipients exacerbates the disease. Adoptive transfer of splenic cells converted acute EAE into CR-EAE in the naive recipients. In light of the different roles of the spleen and LNs in the evolution of CR-EAE, we examined by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) whether a differential mRNA expression profile of cytokines and cellular adhesion molecules (CAMs) in spleen versus LN was associated with relapse or remission in CR-EAE. All the cytokines tested (interleukin-1beta (IL-1beta), IL-2, IL-4, IL-7, IL-10, interferon-gamma (IFN-gamma)) as well as CAMs (ICAM-1, ICAM-2, VCAM-1, LFA-1 and CD44) were expressed at substantial levels in both spleen and LNs. Interestingly, disease remission was found to be associated with an increased mRNA expression of IL-2 and IFN-gamma in LNs and a decreased IL-10 mRNA level in the spleen. On the other hand, an increased mRNA expression of VCAM-1, LFA-1 and CD44 was observed in the spleens in comparison with that in LNs of mice, with remission. During relapses, mRNA expression of the tested molecules did not significantly differ between spleens and LNs. Our results suggest that a differential and polarized expression profile of certain cytokines and CAMs in spleen versus LN could provide molecular correlates of the cyclic pathogenesis of CR-EAE.

Relative resistance to nasally induced tolerance in non-obese diabetic mice but not other I-A(g7)-expressing mouse strains

I-A(g7) is a unique class II MHC molecule that is clearly associated with autoimmune diabetes in non-obese diabetic (NOD) mice. To determine if I-A(g7) is defective in its ability to deliver tolerogenic signals in vivo, H-2(g7) mice were nasally pretreated with antigen, prior to immunization, to induce antigen-specific regulation. Nasally pretreated NOR (H-2(g7)) and (NON).NOD (H-2(g7)) congenic mice showed responses similar to those of NON (H-2(nb1)), BALB/c (H-2(d)) and B10.PL (H-2(u)) mice-a reduced recall response and a deviated T(h) cytokine profile. However, we found that NOD (H-2(g7)) mice are comparatively resistant to immunological tolerance induced by nasal pretreatment, such that at the usually effective dose no significant reduction was seen in the proliferative recall responses to nominal antigen after immunization. (NOD x BALB/c)F(1) (H-2(g7/d)) and (NOD x NOR)F(1) (H-2(g7)) mice were similarly resistant to nasal-induced tolerance, although significantly higher nasal doses of antigen were able to overcome the resistance in NOD and F(1) mice. Interestingly, activated NOD T cells were resistant to cell death induced by re-stimulation with plate-bound anti-CD3. These results demonstrate that activated T cells in NOD mice are defective in their ability to respond to regulatory signals delivered in vivo or in vitro. Furthermore, NOD T cells have an increased resistance to tolerance induced by I-A(g7)-dependent (antigen) or I-A(g7)-independent (anti-CD3) mechanisms. Thus, while I-A(g7) may contribute to insulin-dependent diabetes mellitus by selecting a particular repertoire of self-reactive T cell clones, additional defects in the peripheral T cells themselves are required to allow the expansion of diabetogenic clones and the development of autoimmune disease.

Single dose intranasal administration of retinal autoantigen generates a rapid accumulation and cell activation in draining lymph node and spleen: implications for tolerance therapy

BACKGROUND/AIMS

A single intranasal delivery of retinal autoantigen suppresses effectively experimental autoimmune uveoretinitis (EAU). To further unravel underlying mechanisms the authors wished to determine, firstly, the kinetics of antigen delivery and, secondly, the early cellular responses involved in the initial stages of nasal mucosal tolerance induction.

METHODS

Flow cytometry, cell proliferation assays, and microscopy were used to track antigen following a single, intranasal dose of Alexa-488 labelled retinal antigen.

RESULTS

A rapid accumulation of antigen within both superficial cervical lymph nodes (SCLN) and spleen was observed after 30 minutes. Significant proliferative responses to IRBP were elicited by 48 hours indicating that systemic priming of naive T cells to retinal antigen had occurred. Cell activation was further confirmed by immunoprecipitation studies, which demonstrated phosphorylation of STAT4 but not STAT6 in both lymph nodes and spleen. However, at 24 hours, STAT4 heterodimerisation with STAT 3 was only observed in spleen.

CONCLUSIONS

The results provide novel evidence that following a single intranasal application rapid transfer of antigen occurs. Resulting T cell proliferation develops consequent to differential cell signalling in SCLN and spleen. Further understanding of these underlying cellular mechanisms, in particular as is inferred by the results the contribution of local versus systemic tolerance induction, may assist in strategies to clinically apply mucosal tolerance therapy successfully.

Total dose and frequency of administration critically affect success of nasal mucosal tolerance induction

AIMS

Nasal tolerance induction with autoantigens can effectively protect against a variety of experimental models of autoimmune disease. The aims of this study were to characterise the dosage and kinetics of inhibition of experimental autoimmune uveoretinitis (EAU) via intranasal administration of the uveitogenic antigen interphotoreceptor retinal binding protein (IRBP) in the murine model of IRBP induced EAU.

METHODS

B10RIII mice were tolerised by intranasal administration of IRBP either with a long term multiple low dose or a short term/high dosing regimen before subcutaneous immunisation with IRBP in complete Freund's adjuvant (CFA). On day 15 post-immunisation, mice were killed and eyes were removed for histological examination and quantification of inflammatory cell infiltration and degree of target organ (rod outer segment, ROS) destruction.

RESULTS

Nasal administration of multiple low doses of IRBP (1 microg or 3 microg IRBP per mouse per day for 10 days) significantly protected mice from IRBP induced EAU. Short term/high dose regimens were only effective when given either as a single or, at most, as two consecutive doses (40 microg per dose). Multiple doses in the range of 45-120 microg over 3 days afforded no protection.

CONCLUSIONS

These results indicate that both dose and frequency of intranasal antigen administration are pivotal to tolerance induction and subsequent suppression of T cell mediated autoimmune disease.