Background—Accumulating evidence suggests that several subsets of regulatory T cells that actively mediate immunologic tolerance play crucial roles in atherogenesis. Recently, orally administered anti-CD3 monoclonal antibody has been shown as an inducer of novel regulatory T cells expressing latency-associated peptide (LAP) on their surface, which potently prevents systemic autoimmunity. In the present study, we hypothesized that oral anti-CD3 antibody treatment may inhibit atherosclerosis in mice.

Methods and Results—Six-week-old apolipoprotein E–deficient mice on a standard diet were orally given anti-CD3 antibody or control immunoglobulin G on 5 consecutive days, and atherosclerosis was assessed at age 16 weeks. Oral administration of anti-CD3 antibody significantly reduced atherosclerotic lesion formation and accumulations of macrophages and CD4⁺ T cells in the plaques compared with controls. We observed a significant increase in LAP⁺ cells and CD25⁺Foxp3⁺ cells in the CD4⁺ T-cell population in anti-CD3–treated mice, in association with increased production of the antiinflammatory cytokine transforming growth factor- and suppressed T-helper type 1 and type 2 immune responses. Neutralization of transforming growth factor- in vivo abrogated the preventive effect of oral anti-CD3 antibody.

Conclusions—Our findings indicate the atheroprotective role of oral anti-CD3 antibody treatment in mice via induction of a regulatory T-cell response. These findings suggest that oral immune modulation may represent an attractive therapeutic approach to atherosclerosis.