Suppression of murine SLE by oral anti-CD3: inducible CD4+CD25-LAP+ regulatory T cells control the expansion of IL-17+ follicular helper T cells

Oral administration of Alequel, a mixture of autologous colon-extracted proteins for the treatment of Crohn's disease

The pathogenesis of Crohn's disease involves an immune-mediated damage to the gut mucosa. Current developed therapies are based on the use of immunosuppressive drugs that can lead to significant drug-related adverse responses. There is a need for a therapeutic strategy that is more specific and less global in its effect on the immune system. Oral tolerance is an active process wherein oral administration of antigens is associated with the induction of regulatory cells and the suppression of effector cells directed toward specific and nonspecific antigens. Studies in animal models of experimental colitis suggest that oral administration of proteins extracted from the gut can induce tolerance and alleviate the disease symptoms. Recent clinical trials showed that oral administration of Alequel, an autologous protein-containing colon extract, to patients with Crohn's disease is safe and may be effective as a therapeutic modality for treating the disease. This treatment was associated with disease-associated antigen alterations of the immune response in the patients. Oral administration of Alequel could provide a patient-tailored approach that is side-effect-free for the treatment of patients with Crohn's disease.

Lupus nephritis: lessons from murine models

Lupus nephritis is a challenging clinical condition for which current therapies are unsatisfactory with respect to both remission induction and unwanted toxic effects. Despite intervention, the rates of end-stage renal disease seem to be increasing in the USA. Discoveries over the past decade have greatly improved our understanding of immune activation and effector inflammatory pathways in lupus nephritis; however, this increased understanding has not yet translated into the approval of an effective new therapeutic agent. An analysis of the mechanisms of action of novel immunomodulatory drugs in multiple models of murine lupus clearly shows that interacting networks of immune and effector pathways are recruited as the disease progresses. Reversing established disease by targeting a single cell population or inflammatory pathway is, therefore, difficult once long-lived autoreactive lymphocyte populations are present and peripheral organs are inflamed. Data from murine models of lupus suggest that we need to consider new paradigms for the management of systemic lupus erythematosus that include earlier immune intervention, long-term maintenance therapies and protection of target organs.

Oral administration of OKT3 monoclonal antibody to human subjects induces a dose-dependent immunologic effect in T cells and dendritic cells

INTRODUCTION

Parenteral OKT3 is used to treat transplant rejection and a humanized anti-CD3 Mab has shown positive clinical effects in new onset diabetes. Oral administration of anti-CD3 has not been tested in humans, but suppresses autoimmunity in animal models. Beta-glucosylceramide enhances NKT cell and regulatory T cell activity and enhances the effects of oral anti-CD3 in animals.

MATERIALS AND METHODS

Fifteen healthy volunteers (three per group) received orally administered OKT3 over a dose range of 0.2 to 5.0 mg daily with or without beta-glucosylceramide 7.5 mg for 5 days. Safety and immune parameters were measured on days 5, 10, and 30.

RESULTS AND DISCUSSION

Oral OKT3 enhanced T cell proliferation, suppressed Th1 and Th17 responses by 43% and 41%, respectively, increased TGF-beta/IL-10 expression and decreased IL-23/IL-6 expression by dendritic cells, and affected the IgG repertoire as measured by antigen arrays. Co-administration of oral beta-glucosylceramide induced similar effects. No side effects were observed and no subjects developed human anti-mouse antibodies.

CONCLUSION

These findings demonstrate that oral anti-CD3 monoclonal antibody is safe and biologically active in humans and presents a new avenue for the treatment of autoimmune diseases.

Oral tolerance

Multiple mechanisms of tolerance are induced by oral antigen. Low doses favor active suppression, whereas higher doses favor clonal anergy/deletion. Oral antigen induces T-helper 2 [interleukin (IL)-4/IL-10] and Th3 [transforming growth factor (TGF)-beta] T cells plus CD4+CD25+ regulatory cells and latency-associated peptide+ T cells. Induction of oral tolerance is enhanced by IL-4, IL-10, anti-IL-12, TGF-beta, cholera toxin B subunit, Flt-3 ligand, and anti-CD40 ligand. Oral (and nasal) antigen administration suppresses animal models of autoimmune diseases including experimental autoimmune encephalitis, uveitis, thyroiditis, myasthenia, arthritis, and diabetes in the non-obese diabetic (NOD) mouse, plus non-autoimmune diseases such as asthma, atherosclerosis, graft rejection, allergy, colitis, stroke, and models of Alzheimer's disease. Oral tolerance has been tested in human autoimmune diseases including multiple sclerosis (MS), arthritis, uveitis, and diabetes and in allergy, contact sensitivity to dinitrochlorobenzene (DNCB), and nickel allergy. Although positive results have been observed in phase II trials, no effect was observed in phase III trials of CII in rheumatoid arthritis or oral myelin and glatiramer acetate (GA) in MS. Large placebo effects were observed, and new trials of oral GA are underway. Oral insulin has recently been shown to delay onset of diabetes in at-risk populations, and confirmatory trials of oral insulin are being planned. Mucosal tolerance is an attractive approach for treatment of autoimmune and inflammatory diseases because of lack of toxicity, ease of administration over time, and antigen-specific mechanisms of action. The successful application of oral tolerance for the treatment of human diseases will depend on dose, developing immune markers to assess immunologic effects, route (nasal versus oral), formulation, mucosal adjuvants, combination therapy, and early therapy.