IMMUNOREACTIVITY OF THE JK-132 MONOCLONAL-ANTIBODY DIRECTED AGAINST BASEMENT-MEMBRANE COLLAGEN IN NORMAL AND DIABETIC GLOMERULI

The possible involvement of basement membrane-associated collagen (rec ognized by the monoclonal antibody JK-132) in the evolution of diabeti c nephropathy was studied in kidney specimens from seven patients with noninsulin-dependent diabetes mellitus, and its distribution was comp ared with those of antibodies against alpha 1 to alpha 4 chains of typ e IV collagen. JK-132, a monoclonal antibody against basement membrane -associated collagen, reacted immunohistochemically exclusively with t he mesangial matrix of the glomerular capillary. In contrast, antibodi es to the alpha 1 and alpha 2 chains (IV) reacted strongly with mesang ial matrix, and less strongly with the glomerular basement membrane (G BM). Antibodies to the alpha 3 and alpha 4 chains (IV) reacted mainly with GBM. In diabetes, JK-132 reacted most extensively with the expand ed mesangial matrix, its staining intensity increasing with progressio n of the diabetic glomerulosclerosis. Antibodies to the al and alpha 2 chains (IV) reacted prominently with the expanded mesangial matrix bu t less strongly with the GBM. Antibodies to the alpha 3 and alpha 4 ch ains reacted intensely with the thickened GBM. These results suggest t hat basement membrane-associated collagen differs from alpha 1 to alph a 4 chains of type IV collagen and that basement membrane-associated c ollagen is a good marker of mesangial expansion in diabetic nephropath y.