ARTHRITIS & RHEUMATISM Vol. 44, No. 8, August 2001, pp 1917–1927 © 2001, American College of Rheumatology Published by Wiley-Liss, Inc. Importance of Dose of Type II Collagen in Suppression of Collagen-Induced Arthritis by Nasal Tolerance Catherine J. Derry, Nicola Harper, D. Huw Davies, John J. Murphy, and Norman A. Staines Objective. To determine the influence of the dose of collagen given nasally on the induction of specific mucosal tolerance in collagen-induced arthritis. Methods. The severity of clinical arthritis induced in DBA/1 mice was studied after the nasal administra- tion (before disease induction) of 1 of 4 doses (across a 2-log range) of bovine type II collagen (CII). Parameters of immunity included lymphocyte proliferation and cy- tokine production in vitro in response to antigen stim- ulation, and the production of anticollagen IgG anti- body subclasses. Results. The 3 highest doses (20, 80, and 320 g) ameliorated disease severity, whereas the lowest dose (5 g) aggravated disease. These findings correlated well with antigen-specific T cell proliferation and cyto- kine and antibody production. T cell proliferation was suppressed by the higher doses of CII, whereas the low dose enhanced T cell proliferation, indicating it primed the T cells. Suppression of T cell proliferation could be overcome by the addition of exogenous interleukin-2 (IL-2) to these cultures. Decreased T cell prolifera- tion was associated with suppression of both Th1 (interferon- [IFN]) and Th2 (IL-4) cytokines and all the subclasses of anticollagen IgG in mice receiving 20, 80, or 320 g of collagen. Overall, the highest dose of collagen (320 g) was less effective at suppressing the immune response and disease than the 20-g or 80-g doses. There was an increased production of antibodies of all IgG isotypes, and of the Th1-associated cytokines IFN and IL-2, in animals that had received the lowest dose of 5 g collagen nasally. Conclusion. Nasal administration of antigens is effective in inducing tolerance and reducing disease severity, but the effects are dose dependent. Low doses can prime the immune system and aggravate disease; high doses may not suppress disease. Suppression of the immune response, which correlates with suppression of disease, is not obviously associated with a type I to type II T cell switch, but rather with an overall suppression of both forms of T cell response, with a potential role for anergy of T cells in this process. The mucosal administration of an antigen is an effective way to induce systemic immunologic tolerance to the antigen. Since the first demonstration that induc- ing mucosal tolerance, by giving type II collagen (CII) orally, could prevent the development of collagen- induced arthritis (CIA) in rats (1) and mice (2), other studies have illustrated the general principle that differ- ent experimental arthropathies can be prevented or ameliorated by giving CII or other appropriate antigens or their peptides orally or nasally (3–11). The effective- ness of induced oral or nasal tolerance in controlling arthritis extends to many other experimental auto- immune conditions (for review, see refs. 12–14). In turn, results of several clinical trials in humans have suggested that mucosal tolerance may have a place in the treat- ment of autoimmune diseases such as rheumatoid ar- thritis (RA) (15–18), multiple sclerosis (19), and uveitis (20). However, the modest clinical effect shown in the trials indicates that many aspects of mucosal tolerance induction need to be understood before it can become an established therapy. At a practical level, a number of factors influence the outcome of giving an antigen mucosally with a view to inducing systemic tolerance. These include the nature and physical form of the antigen, the timing of its administration, the use of adjunctive agents, and the Supported by grants S0180 and S0602 from the Arthritis Research Campaign (UK) and grants 43569 and 53356 from the Wellcome Trust. Catherine J. Derry, PhD, Nicola Harper, MSc, D. Huw Davies, PhD, John J. Murphy, PhD, Norman A. Staines, PhD: King’s College London, London, UK. Address correspondence and reprint requests to Catherine J. Derry, PhD, Infection & Immunity Research Group, Division of Life Sciences, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NN, UK. Submitted for publication December 8, 2000; accepted in revised form March 14, 2001. 1917