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At least 73 records · Page 4Linked to original sources
PubMed1986

Homogeneous determination of C-reactive protein in serum using liposome immune lysis assay (LILA).

Recently, we have developed an analytical system based on a complement dependent liposome immune lysis assay (LILA) to measure antibody against protein antigens. This paper describes the application of LILA to measure protein antigens by inhibition reaction. We choose human C-reactive protein (CRP), one of acute phase reactants, for a model of antigen determination. CRP antigen is coupled to the carboxyfluorescein entrapped multilamellar liposomes by using N-hydroxysuccinimidyl 3-(2-pyridyldithio) propionate and dithiothreitol, and a specific lysis of liposomes is achieved upon the addition of anti-CRP antibody in the presence of complement. Inhibition of this assay can be observed by the addition of competing amounts of CRP in human serum. This inhibition assay is simple, fast, highly sensitive, reproducible and homogeneous. The assay covers the ranges 10-500 micrograms/l. In an experiment using 50 samples, the results by LILA correlated well with those by single radial immunodiffusion and enzyme immunoassay (correlation coefficient: 0.99 and 0.93, respectively).

Antigens↗
PubMed1991

Characterization of three monoclonal antibodies to membrane co-factor protein (MCP) of the complement system and quantification of MCP by radioassay.

MCP is a widely distributed regulatory glycoprotein of the complement system which binds C3b and C4b and has factor I-dependent co-factor activity. Monoclonal antibodies raised to lymphocytes (E4.3), chorionic microvilli (GB24) and an embryonal carcinoma cell line (TRA-2-10) recognize MCP (CD46). GB24 inhibited both the binding of MCP to its ligand iC3 and co-factor activity; E4.3 and TRA-2-10 did not. The binding of GB24 to cells bearing MCP was not cross-inhibited by E4.3 or TRA-2.10, but TRA-2-10 blocked binding and displaced pre-bound E4.3. Using these antibodies, we developed a radioassay for quantifying the number of MCP molecules/cells. Human peripheral blood mononuclear (PBMC) and polymorphonuclear cells (PMN) had about 10,000 MCP cell; platelets had about 600/cell, and no MCP was found on erythrocytes. Neoplastic hematopoietic cell lines, of myelocytic and T lymphocytic origin, had several-fold more (20-60,000) molecules cell than peripheral blood cells or B cell lines (about 12,000). Malignant epithelial cell lines. HeLa (about 100,000/cell) and HEp-2 (about 250,000 cell) had the highest MCP expression of any cells examined. These monoclonal antibodies--especially GB24, which blocks MCP function--and the direct binding assay will facilitate the further analysis of the biology of this complement regulatory protein.

Antibodies, Monoclonal↗
PubMed2005

Estrogens and glucocorticoids have opposing effects on the amount and latent activity of complement proteins in the rat uterus.

The mammalian uterus faces unique immunological challenges. It must nurture and protect the semiallogenic fetus from attack by the maternal immune system while guarding against infection by pathogens that compromise fetal and maternal health. Complement has recently been implicated in the etiology of pregnancy loss, but its regulation by steroid hormones and its role in host defense in the uterus are not clearly defined. Here we use biochemical, functional, and physiological assays to elucidate the regulation of complement proteins in the rat uterus. We demonstrate that estrogens (17 beta-estradiol) and glucocorticoids (dexamethasone) have major, but opposing, effects on the amount and latent activity of complement effectors in the uterus. Treatment with 17 beta-estradiol induced vasodilation and an increase in vascular permeability, which resulted in extravasation of plasma and complement into the uterus, rather than de novo complement biosynthesis. In vitro assays revealed that 17 beta-estradiol induced a potent bactericidal activity in uterine luminal fluid and that the antibacterial component was complement. These proinflammatory and immunomodulatory effects were evident within 4 h of treatment and were blocked by coadministration of dexamethasone. We also found that estrogen effects on the vasculature were mediated in part by activation of the contact system and bradykinin B1 receptors. These results indicate that complement plays a central role in innate immunity in the female reproductive tract and suggest that estrogens or glucocorticoids might be used therapeutically to enhance or inhibit complement-dependent processes in the uterus.

Animals↗
PubMed1963

Chromatographic resolution of the first component of human complement into three activities.

A euglobulin fraction of human C'1 has been chromatographically resolved into three distinct activities, designated C'1q, C'1r, and C'1s, in the order of their elution from DEAE cellulose. All three of these activities have been shown to participate in various hemolytic reactions requiring C'1, including the cold phase of the Donath-Landsteiner reaction, and to be necessary for generation of C'1 esterase. C'1q was identical with a previously described serum protein implicated in a very early step of complement action and designated the 11S component on the basis of its sedimentation constant. C'1r could not be related to a known complement activity and has been presented as a new component. C'1s, on the basis of chromatographic evidence, was identified with C'1 proesterase. Methods of assay of these components of C'1 have been presented. The significance of C'1q, C'1r, and C'1s in generation of C'1 esterase and the central role of this enzyme in reactions involving C'1, C'4, and C'2 have been discussed.

Blood Proteins↗