Role of leucocyte adhesion molecules in aminonucleoside of puromycin (PAN)-associated interstitial nephritis

Rats receiving a single dose (10 mg/l00 g body wt) of PAN develop severe proteinuria and acute interstitial nephritis. To investigate the mechanisms involved in interstitial leucocyte accumulation, we examined the expression of adhesion molecules on kidney tissue sections as well as on endothelial cell cultures. We also performed in vivo treatments with antibodies against adhesion molecules. Enhanced expression of intercellular adhesion molecule-1 (ICAM-1) was found on day 7 of the disease, when interstitial nephritis was first detected. Also, rat endothelial cells in culture showed maximal expression of ICAM-1 in the presence of 10(-9) - 10(-11) M PAN. Adhesion of peripheral blood mononuclear cells (PBMC) on kidney sections from PAN-treated rats was highest on day 7 (3.05 +/- 0.7 (mean +/- s.e.m.); controls 0.75 +/- 0.5). Such increased adhesion was notably blocked after PAN-treated rat kidney sections were incubated with anti-ICAM-1 MoAb (0.9 +/- 0.4). In addition, adhesiveness of PBMC to PAN-stimulated endothelial cells in culture was enhanced (25 +/- 2.5%; non-stimulated cells 13 +/- 3.1%). The addition of specific MoAbs against ICAM-1 and lymphocyte function-associated antigen-1 (LFA-1) produced a high blockage of adhesiveness induced by exposure to PAN (inhibition 58 +/- 3%; non-stimulated cells 40 +/- 7%). Simultaneous administration to PAN-treated rats of anti-LFA-1 and anti-ICAM-1 MoAbs reduced the number of interstitial cells by 70% compared with the 30% of reduction obtained when anti-very late antigen-4 (VLA-4) MoAb and anti-vascular cell adhesion molecule-1 (VCAM-1) antibodies were used. Our results suggest that the LFA-1/ICAM-1 pathway plays a principal role in the interstitial nephritis occurring in rats with PAN-nephrosis.