Histomorphologic assessment of serum thymic factor treatment of [formula omitted] mice

Abstract

Subcutaneous injections of synthetic serum thymic factor (1 ng/day, 5×/week, 92–138 doses) exerted a sparing effect in female NZB NZW mice against exacerbation of the renal changes and depletion of small lymphocytes in the T-cell-dependent areas of the spleen and mesenteric lymph nodes which occurred in placebo control mice. No preventive therapeutic effect was apparent in the synthetic serum thymic factor-treated mice when compared with the untreated control mice of similar age. With the onset and development of the renal lesions in the treated and untreated NZB NZW mice, plasma cells became increasingly prominent in the splenic and nodal T-cell-dependent areas. This was followed by plasma cell regression and finally by atrophy of the lymphoid organs including the thymus with the onset of renal glomerular sclerosis. In parallel experiments designed to clarify the role of the thymus in influencing autoimmune pathologic changes, neonatal thymectomy accelerated depletion of small lymphocytes and proliferation of plasma cells in the T-cell-dependent areas of the spleen and mesenteric lymph nodes. Neonatal thymectomy also increased severity of the renal lesions in males, but not in females. By contrast, no signs of the disease were apparent in 17-week-old male NZB NZW mice following adult thymectomy at 4 to 6 weeks of age. Also, by 37 weeks of age, the renal changes and distribution of lymphoid cells in the spleen or mesenteric lymph nodes of adult thymectomized males were not different than in sham-operated animals. However, the depletion of small lymphocytes in the mesenteric lymph nodes from the older adult thymectomized animals was much greater than in the unoperated animals of similar age.