Mucosal immunoregulation involves the unique cross-talk between epithelial cells and various immune system components. Mucosal secretions contain significant quantities of immunoglobulin (Ig) G. The neonatal Fc receptor for IgG (FcRn) is important in regulating host IgG levels and in transporting IgG and its associated antigens across polarized epithelial barriers. Through its ability to secrete and absorb IgG, FcRn integrates its encounters with luminal antigens with the systemic immune compartments. The FcRn thereby provides essential host defense and immunoregulatory functions at mucosal surfaces. In this review, we examine recent data on the use of FcRn and anti-CD3 for immune modulation. Recent preclinical studies have revealed the significant efficacy of using FcRn or orally administered antibodies as a means of immune modulation. For example, the oral administration of anti-CD3 was recently shown to be effective in the prevention and treatment of several animal models of immune-mediated disorders. In addition, the use of FcRn or orally administered antibodies were recently described in two patents as potential methods for inducing systemic tolerance and for treating immune-mediated disorders. The FcRn patent generally discussed the methods and products for initiating an immune response against an antigen. In particular, this patent described the trans-epithelial delivery of antigens to provoke tolerance and immunity. The anti-CD3 patent emphasized the advantages of an oral route of administration compared to a parenteral one. These advantages included easier chronic use and a reduction in the side effects that are associated with the parenteral use of anti-CD3.
- Gut immune system
- Neonatal Fc receptor