Candida albicans cell-wall fraction exacerbates collagen-induced arthritis in mice.

The immune system generates a specific response against most pathogens, while developing tolerance to self-antigens. Commensal micro-organisms can express molecular structures that mimic self-epitopes. During acute infection, such pathogen may activate self-reactive T-cell clones promoting autoimmunity. In the present study, a beta-mercaptoethanol cell-wall fraction (MF) from Candida albicans was injected into the paw of naive ICR and BALB/c mice and into the paw of ICR mice with bovine collagen type II-induced arthritis (CIA). Development of inflammation was monitored for 6 weeks. MF provoked a stable swelling and histopathologic changes in the injected joint, with a predominance of T-helper 1 cytokines in ICR mice. In BALB/c strain, a swelling was observed only in the early period, with no evidence of joint pathology. Injection of the MF fraction exacerbated the disease in ICR mice with CIA, and this was associated with the elevation of interferon-gamma and anti-bovine type II collagen (bCII) immunoglobulin G2a antibodies. These results indicate that component(s) in the MF fraction cross-react with bCII-specific cells.