The source of IgM and IgG in the dog intestine

The source of IgM and IgG2a,b in the dog intestine was investigated, using labelled dog immunoglobulins and chronic Thiry-Vella loops of dog small intestine. Clearancess of IgM and IgG2a,b from serum into intestinal secretions were similar, reflecting transfer of a greater mass of IgG2a,b than of IgM. Only 20% of the intestinal IgM derived from serum, irrespective of the marker used. About one third of the total intestinal IgG, of all sub-classes and accrued from all sources, was serum-derived IgG2a,b. This indicates that serum is a major contributor to dog intestinal IgG2a,b.