This invention discloses methods and compositions for modulating immuneresponses, which involve particulatedelivery of agents to immune cells, wherein the agents comprise an inhibitorof the NF-.kappa.B signaling pathway and an antigen thatcorresponds to a target antigen. The methods and compositions of the presentinvention are particularly useful in the treatment orprophylaxis of an undesirable immune response associated with the targetantigen, including autoimmune diseases, allergies andtransplantation associated diseases.