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At least 667 records · Page 37Linked to original sources
PubMed1975

Complement activation by a univalent hapten-antibody complex.

The univalent hapten, nonadeca lysyl epsilon-Dnp-lysine, binds tightly to rabbit anti-2,4-dinitrophenyl antibody, and the complex has a sedimentation coefficient of 6.7, characteristic of a single antibody molecule. In this communication, we show that this complex is a good activator of the serum complement system. For activation to occur, the univalent hapten must contain the specific group which binds to the antibody, and also the polycationic chain. In addition, activation requires a functional complement-binding region on the intact antibody molecule. The classical pathway appears to be involved since the first, fourth, and second components of complement are markedly depleted when the complement system is activated by this univalent hapten-antibody complex.

Animals↗
PubMed1975

[Immunologic study of subacute infectious endocarditis through the search for circulating immune complexes. Preliminary results apropos of 13 cases].

The detection of circulating immune complexes by precipitation by polyethylene glycol represents a valuable technique of study in sub-acute bacterial endocarditis. In a series of 13 patients, this measurement was carried out, confirming the quasi-constant presence of circulating immune complexes in active S.B.E. This might be of diagnostic value in forms with negative blood culture and, further, make it possible, subsequently, to find the antigen responsible by dissociation of the circulating immune complexes.

Adult↗
PubMed1975

Complement activation in seropositive and seronegative rheumatoid arthritis. 125I-C1q binding capacity and complement breakdown products in serum and synovial fluid.

1. The detection and quantitation of immune complex-like material in synovial fluid and in serum from patients with joint diseases was done through the measurement of the capacity to bind radiolabeled C1q. It was found that 65% of synovial fluid samples from seropositive or seronegative RA patients had a high C1q binding capacity as compared to other joint diseases. Immune complex-like material was also detected in 63% of serum samples from seropositive RA patients. 2. The existence of C3 or C3PA breakdown products in synovial fluid from most of the synovial fluids from RA patients probably reflects an activation of the complement system occurring in both forms of the disease. C3PA breakdown products were never found in degenerative or post-traumatic joint diseases and only occasionally in other inflammatory arthritis. Apart from their pathogenic significance, these results may have some interest for the clinical investigation of patients with joint diseases.

Arthritis, Rheumatoid↗
PubMed1975

The c 1 fixation and transfer test for studying immunity in melanoma patients.

Sera from 27 melanoma patients and from 30 healthy persons were investigated for humoral immunity by C 1 fixation and transfer test. The number of C 1 molecules fixed to serum treated, sensitized tumor cells and C 1 molecules fixed to these cells in vivo were calculated and the quotient of these values was determined. On the basis of the quotient the patients could be divided into four groups. In Group 1 the serum treatment of cells decreased the C 1 fixation; in these cases the presence of blocking factors can be supposed. In Group 2 the serum treatment did not cause any difference: the patient serum does not contain humoral antibody. In Groups 3 and 4 the C 1 fixation rose slightly and significantly respectively. Work is in progress to find a possible relation of the results with the stage of the disease.

Antibodies, Neoplasm↗
PubMed1975

Activation of the classical and alternate pathways of complement by Corynebacterium parvum.

The immunological adjuvant Corynebacterium parvum has been to activate the alternate pathway of complement in human and guinea-pig serum. Human serum in addition contains anti-C. parvum antibodies leading to activation of the classical complement pathway. The possible role of a C. parvum derived polysaccharide in this activation is considered in relation to the biological effects of the micro-organism.

Agglutination Tests↗
PubMed1976

Clq inhibition of the interaction of collagen with human platelets.

Human Clq, isolated in pure state after affinity chromatography on IgG-Sepharose, inhibited collagen-induced aggregation and release of 14C-Serotonin from prelabeled human platelets. Platelet aggregation induced by ADP or thrombin was not inhibited by Clq. Also, the adherence of platelets to glass surfaces was significantly diminished by Clq. In contrast, aggregated Clq mimicked the effect of collagen in causing platelet aggregation and release of serotonin. It appears that monomeric Clq, which has structural similarities to collagen competes with collagen for specific sites on the platelet surface.

Adenosine Diphosphate↗
PubMed1976

Detection of immune complexes in unheated sera by modified 125I-Clq binding test. Effect of heating on the binding of Clq by immune complexes and application of the test to systemic lupus erythematosus.

The 125I-Clq binding test was modified in order to allow for the detection of immune complexes in native unheated human serum. Indeed, heat-inactivation (56 degrees, 30 min) was found to reduce the Clq-binding activity of immune complexes mixed with native serum. This effect was not observed when EDTA was added to the native serum before mixing the immune complexes. The modified 125I-Clq binding test was performed in two steps: first, the tested native serum sample was incubated for 30 min at 37 degrees C with 0.13 M EDTA in order to prevent the integration of 125I-Clq into the intrinsic Clqrs complex, second, 125I-Clq and polyethylene glycol (final concentration 2.5%) were added to this mixture, and further incubated for 1 hr at 4 degrees C. Under these conditions, free Clq remained soluble whereas Clq bound to macromolecular complexes was precipitated. The competitive effect of intrinsic Clq and the interference of other substances such as DNA or bacterial LPS were very limited. The modified Clq binding test was applied to the clinical investigation of 44 patients with systemic lupus erythematosus; and increased Clq binding activity (Clq-BA) was observed in 91% of the samples. The level of Clq-BA was found to be significantly correlated to the DNA-binding capacity and to the decrease of the level of some complement components.

Antibodies↗
PubMed1976

[Detection of circulating immune complexes by the C1q complement fraction deviation test. 1st application in the study of human glomerulopathies].

The C1q deviation test measures the interference of circulating immune complexes in the fixation of radioactive C1q on target cells. The test was carried out in a large sample of cases of glomerular nephropathies, on the serum of patients with hypertension and on control sera. Positive results were frequently obtained with the sera of patients suffering from acute glomerulonephritis and membranous glomerulonephritis. Positive results were rarer in cases of minimal change discase and of membranoproliferative glomerulonephritis. These results suggest that the deviation of C1q in the serum of patients with various types of glomerulone phropathy may be due to circulating complexes but also to other substances. They indicate that efforts should be continued to isolate and biochemically identify the C1q binding substances in pathological sera.

Acute Disease↗
PubMed1977

Studies of urticaria and acute serum sickness with the C1q precipitin test.

The C1q precipitin test was performed in serum samples from five groups of patients: (1) 20 patients with acomplementemic systemic lupus erythematosus glomerulonephritis (SLE), (2) 2 patients with serum sickness due to the administration of horse serum, (3) 2 patients with serum sickness preceding hepatitis B, (4) 50 patients with chronic urticaria, and (5) 30 normal controls. Positive C1q precipitin tests were found in all patients with SLE and the four cases of serum sickness. Positive tests correlated with depressed serum complement (C3 and C4) levels and were found only in the early phase of serum sickness. Urticaria patients uniformly had negative C1q precipitin tests and normal serum complement levels.

Acute Disease↗