RESUMO
This study was undertaken to investigate the in vivo effects of cyclophosphamide (CY) on subpopulations of macrophages and other types of immune cells including dendritic cells (DCs) as well as on ICAM-1 expression in the spleen of rats. After a single dose of CY (150 mg/kg) was administered to Sprague-Dawley rats by intraperitoneal injection, the rats were sacrificed at 1, 3, 7, 14 and 28 days. The immunocytochemical characterization of the tissues were carried out using the monoclonal antibodies W3/25, OX8, HIS24, 8A2, OX6, OX62, ED1, ED2, ED3, and TLD-4C9 for analysis of macrophage subpopulations, DC(s), CD4(+) and CD8(+) T cells, B cells and ICAM-1 expression in cryostat-cut sections. CY exhibited a profound immunosuppressive effect on CD4(+) and CD8(+) T cells as well as B cells as was expected. However, it was found that CY induced an increase in number of certain subpopulations of macrophages, including ED1(+), ED2(+) and ED3(+) macrophages. Contrarily, CY elicited a decrease in number of DCs. CY induced a conspi-cuous upregulation of ICAM-1 on certain populations of leukocytes. This increased expression of ICAM-1 after CY treatment appears to be related with the recruitment of certain populations of leukocytes. Most of these features began to appear from the first day and reached the maximun on the third and especially, the seventh day, but two weeks after CY administration, these phenomena declined. In conclusion, the present study provided a new insight into the differential effects of CY on various populations and subpopulations of immune cells in the rat spleen.