Recovery of immune responsiveness to rabies vaccine after treatment of mice with cyclophosphamide.

Mice treated with cyclophosphamide (Cy) recovered the ability to mount delayed type hypersensitivity reactions within 3 days. By contrast, antibody production to a T cell independent antigen (E. coli lipopolysaccharide) and to human diploid cell strain rabies vaccine did not occur unless the immunization of Cy-treated mice was delayed for 7-10 days. No significant resistance to rabies infection was recorded at 10 days but was demonstrable if 14 days had elapsed between Cy treatment and vaccination.