The dynamics of serum antibodies and metaplasia of the lung respiratory epithelium in influenza-virus-preimmunized mice subjected to immunosuppression.

Mice preimmunized with influenza virus A Scotland 840/74 H3N2 were given cyclophosphamide or hydrocortisone, then challenged with the same active virus. Serum antibody levels and metaplasia of the respiratory epithelium were followed for the next two weeks. Administration of the immunosuppressors was found to decrease antibody levels, and to delay the appearance of metaplasia by 7 days as compared with controls.