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Biomedical subjects

S Ruddy

Publications and source records attributed to S Ruddy.

At least 55 records · Page 3Linked to original sources
PubMed1982

Solubilization of an activity regulating C3b function from Raji cell membranes.

A fraction of isolated Raji cell membranes solubilized with 2m KBr which was capable of inhibiting C3-dependent rosettes was examined for its ability to inhibit the alternative pathway of complement. It was shown to decrease alternative pathway-dependent haemolysis of sheep erythrocytes and to accelerate decay of factor B from these cells. It had no effect on C2 decay, the classical pathway analog of factor B. Inhibitory activity solubilized from Raji cells was not removed by immunoadsorption with anti-factor H or anti-factor I, two well-characterized serum C3b-control proteins. It also differed in two functional respects from these proteins. Firstly, it failed to result in cleavage of a peptide bone in C3 which is characteristic of factor I; secondly, its inhibitory activity did not synergize with factor I in inhibiting the alternative pathway, unlike factor H. These results suggest that Raji cells contain a regulatory factor in their membranes for the alternative pathway of complement which is distinct from factors H and I.

Burkitt Lymphoma↗
PubMed1981

Localization of the receptors for activated complement on the visceral epithelial cells by the human renal glomerulus by immunoenzymatic microscopy.

Horseradish peroxidase-labeled IgG-anti-IgG immune complexes bearing activated third component of complement, C3, were used as indicator particles for the localization of the complement receptor in the human renal glomerulus. The HRP-labeled IgG-anti-IgG complexes were coated with activated C3 by exposing them to fresh human serum as a source of complement. This represents a more physiologic indicator particle for complement receptor-bearing structures than the synthetic immune complexes previously used. By light microscopy, the deposition of the complexes was restricted to the glomeruli. By transmission electron microscopy, the complexes were selectively associated with the surface of the visceral epithelial cells (podocytes). Complexes exposed to buffer alone or to heat-inactivated human serum failed to adhere to any of the renal structures examined.

Binding Sites↗
PubMed1981

The role of immunoglobulins in alternative complement pathway activation by zymosan. I. Human IgG with specificity for Zymosan enhances alternative pathway activation by zymosan.

Prior absorption of normal human serum (NHS) or C2-deficient human serum (C2D) with zymosan at 0 degrees C results in diminished consumption of C3 and factor B during subsequent incubation of the sera in Mg-EGTA buffer with zymosan at 37 degrees C for 30 min. An acid eluate from the zymosan restores the defect of absorbed NHS and C2D, and also enhances C3 and factor B utilization in hypogammaglobulinemic serum (H gamma S) in a dose-dependent fashion. The activity is specific in that the eluate from zymosan fails to enhance C3 and B depletion in H gamma S or absorbed NHS by lipopolysaccharide or Sepharose. The active component of th zymosan eluate emerges from both Sepharose 4B and Sephacryl S-200 in the region of molecules with m.w. of 150,000. Absorption with protein A-Sepharose removes the activity, demonstrating that it is IgG. Digestion of the IgG with pepsin fails to diminish activity, indicating that the Fc region is not required for activity; reduction to monovalent Fab' fragments, however, abrogates activity. When IgG antibody is bound to Protein A-Sepharose, it fails to enhance C3 depletion in H gamma S by Sepharose, indicating that binding of IgG antibody by the Fab region is necessary for enhancement of alternative pathway activity in human serum.

Antibody Specificity↗
PubMed1981

Cleavage of membrane bound C3bi, an intermediate of the third component of complement, to C3c and C3d-like fragments by crude leucocyte lysosomal lysates and purified leucocyte elastase.

Partial degradation of the biologically-active major fragment of the third complement component (C3b) to C3bi is catalysed by the endopeptidase C3b inactivator (I) and its co-factor, beta 1H globulin (H). Complete degradation to the fragments C3c and C3d requires an additional protease, which can be simulated in vitro by trypsin. This study was designed to identify the in vivo correlate of trypsin. Purified and 125I-labelled C3b bound to sheep erythrocytes was used as substrate. Release of label into the supernate served as an index of proteolysis. The chain structure of the peptides in the supernate or remaining bound to the erythrocytes was assessed by SDS polyacrylamide gel electrophoresis. Significant cleavage of cell-bound C3b was obtained by treatment with I, H and extracts from human peripheral blood leucocyte azurophil granules. Purified elastase also removed label in the presence of I and H. The peptide remaining on the cell had the characteristic 33K molecular weight of C3d. The activity of elastase in cleaving was blocked by alpha-1-anti-trypsin, the chloromethyl ketone, MeO-Suc-Ala-Pro-Val-Ch2Cl and by rabbit antibody to elastase. Thus, elastase purified from azurophil granules of human polymorphonuclear neutrophils (PMN) is a potent catalyst of the cleavage of C3bi to C3c- and C3d-like fragments and may contribute in vivo to the control of complement-mediated inflammation.

Animals↗
PubMed1981

Functional and partial chemical characterization of the carbohydrate moieties of the IgE receptor on rat basophilic leukemia cells and rat mast cells.

The role of the carbohydrate portion of the receptor for IgE in the interaction with IgE was investigated. Membrane carbohydrates of rat basophilic leukemia (RBL) cells and rat mast cells (RMC) were labeled by treating the cells with galactose oxidase followed by [3H]-NaBH4. IgE receptors were separated from detergent solubilized membranes and examined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Pretreatment with neuraminidase markedly increased the incorporation of 3H into both the total membrane extract and into the IgE receptors. SDS-PAGE analysis demonstrated the presence of galactose in all IgE-binding components of 2 RBL cell lines and the presence of sialic acid on the major IgE-binding component. Prior saturation of the cells with IgE did not prevent the carbohydrate labeling of the receptor, although it did block the labeling of its protein part, indicating that carbohydrates are not located in the binding site. Removal of terminal sialic acid residues with neuraminidase increased the affinity of the receptor for IgE without appreciably affecting the number of receptors per cell. In order to more drastically modify the receptor carbohydrates, RBL cells were grown in the presence of Tunicamycin (TN). TN was shown to markedly inhibit the incorporation of [3H]-glucosamine into the receptor. RBL cells grown in the presence of TN expressed fewer receptors at the cell surface, as judged both by ligand binding studies and external labeling procedures. These data cumulatively suggest that the carbohydrate moieties of the receptor are not directly located in the binding site of the IgE receptor; however, the TN studies suggest that receptor carbohydrate may play a role in transport of the receptor to the plasma membrane or in its orientation thereafter.

Animals↗
PubMed1979

Demonstration of beta 1H globulin together with C3 in the dermal-epidermal junction of patients with systemic lupus erythematosus.

Skin lesions and clinically normal skin from 10 patients with systemic lupus erythematosus (SLE) were examined by immunofluorescence for the presence of C3 and its control protein, beta 1H globulin. beta 1Hwas always found in association with deposited C3; in the instance where C3 deposits were not found beta 1H was also not found. Granular deposits of C3 and beta 1H were found in the dermal-epidermal junction (DEJ) in all of the 5 nonlesional skins studied. In the lesional skin, C3 was found in 4 of 5; in 2 of these 4, beta 1H was also found. As previously demonstrated for in vitro systems, beta 1H also binds in vivo to fragments of C3, presumably C3b, generated during activation of the complement system.

Adolescent↗
PubMed1979

Deposition of beta 1H globulin in kidneys of patients with immune renal disease.

Renal biopsies from patients with a variety of immune type renal diseases were examined by immunofluorescence for the presence of C3 and its control protein, beta 1H globulin. Deposits of beta 1H were found in every instance (21 of 21 biopsies) in which C3 deposits were observed, irrespective of the underlying disease resulting in the C3 deposits, including lupus nephritis, acute poststreptococcal glomerulonephritis, idiopathic membranous glomerulonephritis, and Goodpasture's syndrome. In no instance was beta 1H found independently of C3. As previously shown in in vitro systems, beta 1H also binds to C3, presumably C3b, during activation of the complement system in immunologically induced renal disease.

Anti-Glomerular Basement Membrane Disease↗
PubMed1979

Lyme arthritis: correlation of serum and cryoglobulin IgM with activity, and serum IgG with remission.

Forty-eight patients with erythema chronicum migrans (ECM) were studied prospectively for 6 to 18 months. Twenty-six patients had no later symptoms, but 22 subsequently developed Lyme arthritis and 9 of them also experienced neurologic abnormalities. Eighty-seven percent of patients with active ECM followed by subsequent involvement had cryoglobulins containing IgM compared to only 13% of those with active ECM and no later symptoms. The former group also had significantly lower IgG, C3 and C4 levels. Sixty-seven percent of patients still had serum cryoglobulins when neurologic disease was most active, and 45% had them when joint symptoms were most severe, but only 11% continued to have small amounts in remission. The number of patients who continued to have serum cryoglobulins with recurrent attacks of arthritis decreased with time. In contrast, patients always had cryoglobulins in joint fluid, a finding Lyme arthritis shares with rheumatoid arthritis. The cryoprecipitates from 2 of 10 patients contained particles with internal structure, but their viral nature is problematic. All components of antisera obtained from goats and rabbits immunized with cryoglobulins were absorbed by normal human sera. The amount of IgM in cryoglobulins correlated directly with serum IgM, which generally rose during exacerbations and fell during remissions; serum IgG and IgA moved conversely. Thus, IgM was an important correlate of clinical disease activity and IgG or remission.

Adolescent↗
PubMed1979

Demonstration of the complement regulating protein, beta 1H, in skin biopsies from patients with bullous pemphigoid.

beta 1H-globulin is a recently characterized plasma protein which regulates the biologic activities of the major fragment of the third complement component, C3b. The major function of this protein is to act as a co-factor for C3b Inactivator (C3bINA) in the cleavage of C3b to an intermediate molecule, C3b', consisting of an intact beta-chain covalently bound by disulfide bridges to 2 alpha-chain fragments of 40,000 and 67,000 daltons. Final cleavage of C3b' to the C3c and C3d fragments requires an additional protease such as plasmin or elastase. Additionally, beta 1H interferes with the activity of the alternative pathway convertases, C3bBb and C3bBbP, by displacing or competing with the binding of factor B. In this study, perilesional skin biopsies from 10 patients with active bullous pemphigoid were examined for the presence of beta 1H at the dermal-epidermal junction by immunofluorescent methods. The protein was found in 8 of 9 biopsies in which C3 also was deposited. In a single case where C3 was not found, beta 1H was not seen. These findings suggest that beta 1H plays a role in the in vivo control of C3b and provides additional evidence for the participation of the complement system in the pathogenesis of bullous pemphigoid.

Aged↗
PubMed1979

Circulating immune complexes in Lyme arthritis. Detection by the 125I-C1q binding, C1q solid phase, and Raji cell assays.

We have found immunoglobulin (Ig) G-containing material consistent with immune complexes in the sera of patients with Lyme arthritis. It was detected in 29 of 55 sera (55%) from 31 patients by at least one of three assays: (125)I-C1q binding, C1q solid phase, or Raji cell. The presence of reactive material correlated with clinical aspects of disease activity; it was found early in the illness, was most prominent in sera from the sickest patients, was infrequent during remissions, and often fluctuated in parallel with changes in clinical status. The results in the two C1q assays showed a strong positive correlation (P<0.001). They were each elevated in 45% of the sera and were usually concordant (85%). In contrast, the Raji cell assay was less frequently positive and often discordant with the C1q assays. In sucrose density gradients, putative circulating immune complexes sedimented near 19S; they, too, were detected best by the two assays based on C1q binding. An additional 7S component was found in some sera by the (125)I-C1q binding assay. Serum complement was often above the range of normal in patients with mild disease and normal in patients with severe disease but did not correlate significantly with levels of circulating immune complexes. IgM and IgG rheumatoid factors were not detectable. These findings support a role for immune complexes in the pathogenesis of Lyme arthritis. Their measurement, by either the (125)I-C1q binding assay or by the C1q solid phase assay, often provides a sensitive index of disease activity. Moreover, the complexes are likely sources of disease-related antigens for further study of this new disorder.

Adolescent↗
PubMed1979

Relative importance of C3b inactivator and beta 1H globulin in the modulation of the properdin amplification loop in systemic lupus erythematosus.

Serum concentrations of C4, C3, factor B (B), properdin (P), C3b inactivator (C3bINA) and beta 1H globulin have been measured by radial immunodiffusion in sixty-two samples from thirteen patients with systemic lupus erythematosus (SLE). Significant reductions in the mean serum concentrations of C4 (classical pathway) B and P (alternative pathway) and C3 were found. In addition, the mean level of the control protein beta 1H, but not C3bINA, was reduced. Sera from thirteen patients taking during disease exacerbation (low C3) showed significantly lower levels of both C3bINA and beta 1H than sera taken from the same thirteen patients during disease remission (high C3). Serum concentrations of C3bINA correlated with B (P less than 0.005) but not C4, C3 or P, whereas levels of beta 1H correlated with C4 (P less than 0.01), B (P less than 0.005) and properdin (P less than 0.01). Serial measurements of the serum concentrations of C3bINA and beta 1H showed that levels of these protein fell during exacerbation, and such falls were more closely associated with diseases in the serum levels of the alternative pathways proteins than C4. It is concluded from these observations that serum concentrations of the control proteins C3bINA and beta 1H, especially the latter, control the extent of turnover of the alternative pathway in SLE. Metabolic studies are required to determine the causes of the decreased serum concentrations of these control proteins.

Complement Activation↗