Rabbit nasal mucosa: nanospheres coated with polypeptides bound to specific anti-polypeptide IgG are better transported than nanospheres coated with polypeptides or IgG alone.

In rabbit nasal mucosa, polypeptides and polypeptide-coated nanospheres are actively transported from lumen to blood by M-cells present in specialized transport areas of the epithelium. The largest transport is shown here to occur when some molecules of the polypeptides coating the nanospheres, after adsorption, are bound to the specific anti-polypeptide IgG, e.g. when insulin is bound to the anti-insulin IgG. The transport kinetics of nanospheres coated by insulin bound to its antibody, as a function of bead concentration or of the antibody/insulin coating ratio, have been analyzed. On this basis it was possible to assess the maximal transport capacity of the epithelium and to calculate the percentage of M-cells involved.