Impaired Recovery of Plaque-Forming Cells in New Zealand Mice Given Cyclophosphamide Free

An inverse relationship between age and the ability to recover from cyclophosphamide-induced depression of PFC response to sheep erythrocytes was discovered in NZB/NZW mice 3 to 10 weeks of age. Older animals recovered responsiveness more slowly than did Balb/c controls, while younger mice recovered more quickly. Bone marrow but not thymus cells were capable of restoring reactivity in older animals. These findings suggest a deficiency of immunocyte precursors in New Zealand mice at a time prior to the onset of their autoimmune diseases.