Gastrointestinal uptake and blood clearance of antigen in the presence of IgA antibodies.

In selected experiments, IgA antibodies with specificity for dinitrophenyl (DNP) groups appeared to prevent gastrointestinal passage of antigenic fragments of DNP-conjugated protein given orally to mice. The antigen did not, however, pass across the gut as an intact macromolecule even in control animals. IgA was not found to increase the blood clearance of DNP-conjugated protein given intravenously and it is concluded that IgA probably does not have any important role in mediating elimination of macromolecular antigens from the blood.