Figure 1. Sera from LN subjects demonstrate selective reactivity to glomerular and podocyte proteins.
a. Representative immunoblots of individual lupus subjects with human glomerular proteins. Sera at a dilution of 1:200 from individual lupus subjects were immunoblotted against 30 μg of human glomerular proteins. Immunoblots from a lupus subject without nephritis (LC), a lupus subject with proliferative nephritis (PLN), and a lupus subject with membranous nephritis (MLN) are shown.
b. Patterns of sera reactivity to human glomerular proteins among subjects with SLE. Graph demonstrating patterns sera reactivity of individual subjects against human glomerular extracts. 10 subjects with SLE without nephritis (LC), 10 subjects with proliferative lupus nephritis (PLN), and 15 subjects with membranous lupus nephritis (MLN) were compared. The percentage of subjects with reactive bands in each region is displayed.
c. Immunoblots of individual lupus subjects with human glomerular proteins highlighting the region of interest from 36-50 kDa. Sera from individual lupus subjects were immunoblotted against 30 μg of human glomerular proteins at 1:200 dilution. Immunoblots from 10 lupus subjects without nephritis (C1-C10), 10 subjects with proliferative lupus nephritis (P1-P10), and 15 subjects with membranous lupus nephritis (M1-M15) are shown.
d. Human podocyte immunoblot demonstrating separation of membrane and cytosolic fractions. Podocyte plasma membrane (M) and cytosol (C) fractions were probed with antibodies against plasma membrane proteins PLA2R and NAK-α1, and cytosolic WT-1.
e. Immunoblot of pooled sera with human podocyte membrane proteins. Pooled sera from 10 lupus subjects without nephritis (LC), 5 subjects with MLN, and 10 subjects with PLN were immunoblotted against 20 μg of podocyte membrane proteins at 1:10,000 dilution. A reactive band at approximately 50 kDa was seen in the MLN and PLN subjects, but not in the LC subjects.