We studied the effect of cyclophosphamide (CPM) on development of severe glomerular lesions in a model of murine nephrotoxic nephritis (NTN). CPM treatment (300 mg/kg) before initiation of the first phase on NTN showed no host antibody depositions along the glomerular basement membrane, as revealed by immunofíuorescence; however, the histological study revealed no significant difference in the degree of renal damage between the control and the CPM-treated mice. Therefore, the severe glomerular lesions in murine NTN may be induced without antibody response to nephrotoxin, in the glomerulus