Influence of immunosuppressants on the establishment of Paragonimus miyazakii in albino rats.

The present investigation has shown that combined treatment with dexamethasone and prednisolone of with hydrocortisone and dexamethasone enhances the susceptibility of albino rats to Paragonimus miyazakii, presumably by suppressing the host's immune responses. In the rats given these combined treatments, the size and egg production of worms were markedly increased. Use of dexamethasone or prednisolone alone had relatively little influence on the growth and maturity of P. miyazakii. In serological analysis and agar double diffusion, considerable differences were recognized between the gamma-globulin fractions and antigen-antibody systems (precipitin bands) of the treated groups and the untreated group. The mechanism of action of these immunosuppressants in this system remains obscure.