Glomerular sequence of events concerning monocyte/macrophage accumulation and ICAM-1 expression during experimental serum sickness nephritis in the rat

Immunohistochemical characterization of macrophage and dendritic cell subpopulations of the spleen, thymus, tongue and heart in cyclophosphamide-induced immunosuppressed rat

This study was undertaken to investigate the immunohistochemical characterization of different subpopulations of macrophages and dendritic cells (DCs) of the spleen, thymus, tongue and heart in cyclophosphamide (CY)-induced immunosuppressed rat. After CY treatment, remarkably, ED1+, ED2+ and ED3+ macrophage subpopulations, in general exhibited signs of cellular activation such as an increase in number and size of cell, and an upregulation of the ED1, ED2 and ED3 reactive surface molecule expression in all the organs studied, except for some macrophage subpopulations including ED1+ macrophages in the non-lymphoid tissues. Subpopulations of DCs showed a differential sensitivity to CY. Lymphoid DCs were more sensitive to CY than non-lymphoid interstitial DCs. CY induced a conspicuous upregulation of intercellular adhesion molecule-1 (ICAM-1) expression in the vascular endothelial cells, splenic marginal zone and thymic cortex. In this study, we demonstrated the in vivo effects of CY treatment on subpopulations of macrophages and DCs as well as on ICAM-1 expression in the rat spleen, thymus, tongue and heart. Moreover, our results shed more light on the activation effects of CY on certain subpopulations of macrophages, on the differential sensitivity of DCs to CY between the immature and mature ones, on the functional role of different subpopulations of macrophages, and on the significance of upregulated ICAM-1 expression in the splenic marginal zone and thymic cortex after CY treatment.

Cyclosporin A reduces expression of adhesion molecules in the kidney of rats with chronic serum sickness

Treatment with cyclosporin A (CsA) improves proteinuria and reduces renal cellular infiltration in chronic serum sickness (CSS). We examined if these effects were associated with a reduced renal expression of CD54 and its ligands, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and MHC class II molecules. We studied two groups of rats in which CSS was induced by daily injections of ovalbumin (OVA): a group treated with CsA (OVA.CsA group, n = 11) and a group that received no treatment (OVA.CSS group, n = 11). An additional group of five rats (control group) received only phosphate buffer. Immunostaining techniques were used to follow CSS and to study the expression of CD54, CD18, CD11b/c, IFN-gamma, TNF-alpha and MHC class molecules. Proteinuria (mg/24 h) was reduced from 248.2 +/- 73.1 (OVA.CCS group) to 14.5 +/- 13.1 with CsA treatment (P < 0.0001). The renal expression of CD54 and its ligands (CD18 and CD11b/c) was reduced by 50% to 75%. Correspondingly, there was a 60% to 85% reduction in the number of infiltrating leucocytes. The number of cells expressing TNF-alpha, IFN-gamma and MHC II molecules was also reduced. CsA reduces expression of CD54 and its ligands. This effect is associated with a reduction of cellular infiltration, IFN-gamma, TNF-alpha-producing cells and with MHC II expression in the kidney. These findings suggest that expression of adhesion molecules plays a critical role in CSS and underline the importance of cellular immunity in this experimental model.

Expression of adhesion molecules in chronic serum sickness in rats

Peripheral blood leukocytes infiltrate the kidney in chronic serum sickness (CSS). We therefore studied the expression of CD54 and its ligands CD18 and CD11b/c in CSS in 10 rats with CSS, 6 rats immunized similarly who did not developed proteinuria (no-CSS group), and 10 normal rats (control group). Intense (6 to 35 times more than controls) leukocyte infiltration was observed in CSS. The CSS group over-expressed CD54 in glomeruli and interstitium in association with increments in CD18- and CD11b/c-positive cells ranging 2.5 to 7 times the number found in controls. 75% of infiltrating leukocytes expressed CD18 and 87% expressed CD11b/c. The non-CSS group had leukocyte infiltration and expression of adhesion molecules similar to control group. Adherence of CD43-positive cells to renal tissues was 4 times higher in renal tissue from CSS rats than to normal kidney. Pretreatment with corresponding Mabs reduced adherence by half. We concluded that over-expression of CD54 and its ligands CD18 and CD11b/c in infiltrating leukocytes occur in CSS. Binding experiments suggest the functional relevance of these molecules.