Immunological involvement in pulmonary fibrosis induced by peplomycin.

Pulmonary fibrosis in mice induced by peplomycin (PEP) was suppressed by administration of anti-inflammatory agents such as prednisolone and D-penicillamine during or after the administration of PEP. Pulmonary fibrosis was also suppressed by administration of cyclophosphamide, an immunosuppressive antitumor agent before, during or after the administration of PEP. The pulmonary fibrosis in athymic nude mice induced by PEP was less than that in normal mice. The low response in the nude mice was enhanced by transfer of thymocytes to the same level as that in the normal mice. This suggests that the immune system, especially thymus-dependent immunity, is involved in the pulmonary fibrosis induced by PEP.