A new role for complement in experimental @entity8 in XXXX .

@entity35 @entity644 @entity8 @entity8157
The only established role for complement in mediating immunologic @entity8 involves elaboration of leukochemotactic factors and neutrophil-dependent @entity8 . In the passive @entity8157 (PHN) model of experimental @entity8 , @entity35 injected with sheep antibody to @entity35 proximal tubular brush border antigen (Fx1A) form subepithelial deposits of sheep IgG and @entity35 complement (C3), and develop heavy @entity644 after 5 d without glomerular inflammatory changes. To study the role of complement in mediating @entity644 in PHN, 16 @entity35 were treated daily with cobra venom factor from before antibody injection to maintain C3 levels at < 10% of pretreatment values and compared to 16 untreated controls. @entity644 at 5 d was abolished in C3-depleted @entity35 (4 +/- 1, controls 70 +/- 15 mg/d, P < 0.001), although renal deposition of 125I-labeled antibody ws the same in both groups (188 +/- 35 vs. 191 +/- 22 microgram IgG/2 kidneys, P > 0.5). Nephritogenic doses of both the noncomplement-fixing F(ab')2 portion and the gamma 2 subclass of anti-Fx1A IgG produced subepithelial deposits of immunoglobulin without C3, but @entity644 did not occur despite glomerular deposition of up to 70 microgram/2 kidneys of gamma 2. However, glomerular deposition of as little as 60 microgram of gamma 1 produced C3 fixation in vivo and heavy @entity644 . No neutrophil exudate could be detected histologically in PHN from the time of antibody injection through development of @entity644 . @entity644 in five PHN @entity35 depleted of neutrophils to < 200/mm3 with antineutrophil serum was not reduced compared to six controls with normal neutrophil counts (34 +/- 9.6 vs. 25 +/- 10.4 mg/d, P > 0.5). These results demonstrate that @entity644 in the PHN model of @entity8 is complement-dependent and strongly suggest a neutrophil-independent mechanism. Thus a new role for the complement system in mediating immunologic @entity8 is identified.
