It is generally thought that antigens inducing the formation of IgA immune complexes in primary IgA nephropathy and responsible for mesangial immune deposits are of infectious and alimentary origin. To investigate the possible role of alimentary antigens in eliciting the IgA mucosal immune response we studied the reactivity and the formation of mesangial IgA deposits in rodents following different experimental conditions: a) on gluten-free diet and oral immunization with gliadin; b) on gluten and soya free diet and oral immunization with soya; c) on chronic alcoholic intoxication. We found that oral immunization with gliadin induced the formation of mesangial deposits of IgA similar to those observed in human primary IgA nephropathy. On the contrary, oral immunization with soya failed to induce the formation of similar immune deposits even though the lectin components in soya and in gliadin are similar. Chronic ethanol intoxication induced an increase in serum IgA against alimentary antigens suggesting an increase in intestinal permeability due to alcohol. Mean times we observed significant IgA mesangial deposits. Our experimental data suggest that alimentary antigens can play a significant role in inducing primary IgA nephropathy.