Identification of the components of glomerular immune deposits using monoclonal antibodies

Monoclonal antibodies have been raised against components of glomerular immune deposits in experimental glomerulonephritis and idiopathic human glomerulonephritis. An accelerated model of chronic serum sickness in the rat using cationized human serum albumin was employed to obtain renal tissue with capillary loop and mesangial immune deposits. Mice were immunized with isolated rat glomeruli or a preparation of glomerular basement membrane and mouse spleen cells fused with myeloma cells. Anti-human serum albumin monoclonal antibodies were produced from all technically successful fusions irrespective of the size of the deposits in the immunizing tissue or whether whole glomeruli or glomerular basement membrane were used for immunization. Monoclonal antibodies were then produced following immunization with tissue from postmortem human kidneys with idiopathic membranous and mesangiocapillary glomerulonephritis. Sixteen monoclonal antibodies, apparently reactive with glomerular immune deposits, were cloned; most of these were reactive with components of the complement system including a previously undescribed complement-related protein. These studies demonstrate that monoclonal antibody technology may be useful in determining the identity of antigen and non-antigen components of glomerular immune deposits.