Tolerance is dependent on complement C3 fragment iC3b binding to antigen-presenting cells

Systemic tolerance can be induced by the introduction of antigen into an immune-privileged site. Here we investigated the role of complement in the induction of tolerance after intraocular injection. We found that the development of antigen-specific tolerance is dependent on a complement activation product. The ligation of the complement C3 activation product iC3b to complement receptor type 3 (the iC3b receptor) on antigen-presenting cells resulted in the sequential production of transforming growth factor-beta2 and interleukin-10, which is essential for the induction of tolerance. These observations may extend to the development of both neonatal tolerance and other forms of acquired tolerance.     

Significance of CA72.4 in patients with colorectal cancer. Comparison with CEA and CA19.9.

CA72.4 is a new tumor-associated antigen identified by monoclonal antibodies cc49 and B72.3. Serum levels of CA72.4 were measured in patients with benign and malignant diseases. The cut-off used was 4 U/mL. CA72.4 is a highly specific marker since only 3% of 162 patients with benign diseases had elevated levels of antigen. Forty-four percent of 89 patients with colorectal cancer had elevated CA72.4 levels. Compared with CEA and CA19.9, we have found that CEA (75%) is the most sensitive marker (p less than 0.001). The simultaneous use of two or three markers did not further contribute to the evaluation of patients with colorectal cancer.