Search PubMed⌕ Search

Biomedical subjects

A Corvetta

Publications and source records attributed to A Corvetta.

At least 37 records · Page 2Linked to original sources
PubMed1983

The alternative complement pathway control protein H binds to immune complexes and serves their detection.

During solubilization of immune complexes C3b becomes fixed to the immunoglobulin part and serves as a receptor for the alternative complement pathway control protein H. The H-C3b immune complex interaction can be made detectable using 4% polyethyleneglycol to separate free from bound 125I-H. Tetanus toxoid (Te)/anti-Te complexes kept soluble with fresh serum and containing 125 IU of specific antibody bound 18% of 125I-H; when fresh serum was chelated with 10 mM EDTA, 125I-H binding was only 5%. On sucrose density gradients, the H-binding material sedimented in the range of 12 to 30 S. In 36 serum samples from rheumatoid arthritis (RA) patients and in 12 serum samples from patients with systemic lupus erythematosus (SLE), 125I-H binding was significantly elevated to 9.5 +/- 4.7% (mean +/- 1 SD) and 13.3 +/- 5.6%, respectively, while 125I-H binding by 36 normal human sera was 4 +/- 2%. RA samples (17/36, 47%) and SLE samples (9/12, 75%) had H-binding values increased by more than 2 SD above the normal mean. The serum samples were also assessed for conglutinin- and C1q-binding activities; a significant correlation between H and C1q binding was observed (P less than 0.001); there was no correlation between H and conglutinin binding. Although binding to immune complexes through its interaction with C3b, H clearly detects a population of complexes other than conglutinin, thus expanding the possibilities of further characterizing pathological complexes.

Antigen-Antibody Complex↗
PubMed1983

An extended C1q-binding assay using lactoperoxidase- and chloramine-T-iodinated C1q. Immediate distinction between immune-aggregate-mediated and non-immune-aggregate-mediated C1q binding.

An extension of the C1q-binding assay for the detection of immune-aggregate-mediated and non-immune-aggregate-mediated C1q binding is reported. The assay involves the use of two different C1q preparations, one radioiodinated by means of lactoperoxidase (LPO-125I-C1q) and the other by means of chloramine-T (CT-125I-C1q). The treatment with CT for 20 min at room temperature before iodination for 1 min led to abolishment of the C1q-binding capacities to complexed IgG: approximately 50% of LPO-125I-C1q but only 2% of CT-125I-C1q bound to 80 micrograms/ml of IgG forming part of tetanus toxoid/anti-tetanus toxoid complexes or to 200 micrograms/ml of heat-aggregated human gamma globulin. Similar results were obtained with staphylococcal protein-A-aggregated IgG. CT-treated C1q was haemolytically inactive. In contrast to the results with complexed IgG, CT treatment did not markedly reduce binding capacities of C1q to heparin: approximately 55% of LPO- and CT-125I-C1q were bound by 127 U/ml of commercial heparin in normal human serum. Both C1q preparations bound to a comparable extent to fibronectin, fibrinogen, and various bacterial endotoxins. When the LPO- and CT-125I-C1q-binding patterns obtained on serum samples from patients with systemic lupus erythematosus, rheumatoid arthritis, or essential mixed cryoglobulinaemia were compared with binding patterns observed using laboratory reactants, an immediate detection of non-immune-aggregate-mediated C1q binding became possible.

Antigen-Antibody Complex↗
PubMed1983

[Radiologic and clinico-serological correlates in rheumatoid arthritis].

In a study of 86 patients with rheumatoid arthritis a valid statistical correlation can be found between the entity of the osteo-articular lesions of the hand and wrist shown by radiography to a high definition and some clinical and serological parameters. The results indicate a good correlation with a large part of the considered parameters (anatomical stage, functional class, duration of the disease, VES, gamma-globulins, serological activity) and confirm the validity of the high definition radiographical study in the follow-up of the disease.

Adult↗
PubMed1983

Complement activation and impaired capacity to solubilize immune complexes or to prevent their formation in essential mixed cryoglobulinemia.

The complement profile, the immune complex solubilizing capacity (ICSC), the immune complex precipitation inhibition capacity (ICPIC), the presence of cryoprecipitable material, and the presence of immune-aggregate- and non-immune-aggregate mediated C1q-binding activity was assessed in serum samples from 23 patients suffering from essential mixed cryoglobulinemia (EMC). No correlation between the levels of cryoglobulins and the clinical activity of EMC was found. The mean C1q-binding activity in EMC serum samples was abnormally elevated 28 +/- 29% (mean +/- SD). In six out of eight serum samples that contained C1q-binding material, evidence was obtained that such material was of the complexed immunoglobulin G (IgG) type. Among the levels of C1q, C1r, C2, C4, C3, C5, C6, C1-inhibitor, C3d, B, I, H, as well as the total hemolytic activity and the activity of the alternative pathway of the complement, the mean serum concentrations of C1, C2, and C4 and in consequence the mean total hemolytic activity were significantly reduced, whereas the mean levels of C3d were significantly elevated in the EMC serum samples. The capacity of the 23 EMC serum samples to solubilize preformed immune precipitates from bovine serum albumin (BSA) and rabbit anti-BSA antibodies as well as their capacity to prevent the formation of the precipitable form of such complexes was analyzed. Compared to the ICSC and the ICPIC of 30 normal human sera, the ICSC and the ICPIC of EMC serum samples were reduced to 57 +/- 24% and 38 +/- 33%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Immune complexes and complement profile in essential mixed cryoglobulinemia before and after plasma exchange.

Five patients affected by essential mixed cryoglobulinemia (EMC) with renal involvement unresponsive to high doses of corticosteroids, have been treated with 16 plasma exchanges (PE). The plasma removed at each apheresis was 1652 +/- 416 ml. The following data were evaluated before and after PE: levels of immune complexes as detected by cryocrit and C1q binding assay; total complement activity (CH50) and alternative pathway complement activity (APCH 50); concentrations of 9 complement components (C1q, C1s, C4, C3, C5, C6, B, I and H) and of the C3 split product C3d. By definition all serum samples had detectable cryoprecipitates and 4 out 5 had C1q binding activity higher than the upper limit of 2 SD. The effect of the PE was the decrease of cryocrit and of C1q binding activity approximately to one half their initial values. The basal complement profile suggested and excessive activation of complement through the classical pathway. Indeed we found low levels of the early complement components (C1q, C1s and C4), reduced CH50, normal levels of C3 and an increase of C3 split product C3d concentrations. APCH50 as well as C5, C6, B, I and H concentrations were found within the normal range. After each PE a significant decrease of the previously normal components was observed. The decrease was independent of the replacement fluid used (5% albumin solution or fresh plasma or cryoglobulin-depleted autologous plasma) and had a short duration. Indeed all these components after the drop following the PE increased rapidly reaching the basal level over a period of 24-48 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Complex↗
PubMed1982

[Circulating immune complexes in a population of subjects seropositive for rheumatoid factor].

The level of immune complexes has been detected with the C1q binding test in 179 subjects positive by Latex agglutination test (titre greater than 1/20). The average of C1q binding was 5.36%, significantly higher than in 30 normal blood donors. A positive correlation was observed between the percent of C1q binding and, respectively, the titre of the latex test and the erythrocyte sedimentation rate. Of the 36 patients with rheumatoid arthritis, 16 (45.7%) showed an high level of C1q binding activity (greater than 5%), as well as 4 of the 8 patients with chronic hepatitis (50%) and 11 of the 31 patients with infectious diseases. No immune complexes were detected among the 11 healthy latex positive subjects.

Antigen-Antibody Complex↗