Plasma complement protein

Hamilton KK, Hattori R, Esmon CT, Sims PJ. Complement proteins C5b-9 induce vesiculation of the endothelial plasma membrane and expose catalytic surface for assembly of the prothrombinase enzyme complex. J Biol Chem 1990 265 3809-3814. 

The activation, maturation, differentiation, and mobilization of immune cells are controlled by cytokines (e.g., interleukins, interferons, and chemokines), which are soluble mediators produced by immune cells and/or by cells outside the immune system (e.g., epithelial cells and cells of the nervous system). Other soluble (humoral) mediators produced by immune cells include antibodies (immunoglobulins) and complement proteins (plasma proteins produced by monocytes and macrophages as well as hepatocytes). Mediators are important in the implementation and regulation of immune responses. 

The ability to label specifically plasma membrane proteins with [ I]ISA makes it possible to analyze the effects of an immune attack system (e.g., antibody-complement) on cell surface proteins and protein-containing macromolecules (e.g., lipoproteins). In this regard, cells can be labeled with [ I]ISA, sensitized with antibody, and treated with com-... 

Fig. 1. Release of [ I]iodosulfanilic acid-labeled plasma membrane proteins from line-10 tumor cells treated with antibody plus complement. — , Tumor cells alone (T) T...

The hepatocytes are the most active sites of protein synthesis, and albumin plays important roles in the transport of bilirubin, anions, fatty acids, several hormones, and xenobiotics. Albumin also is important in determining the colloidal osmotic pressure of plasma and other body fluids. Other proteins synthesized in the liver include the acute-phase response proteins, complement proteins, and the coagulation cascade proteins (see Chapter 8). The levels of plasma proteins reflect the balance between the rates of synthesis, utilization, and degradation. The liver also plays an important role in the metabolism of cholesterol and lipoproteins (see Chapter 9). 

Hulsewe et al. 1997). Several of the plasma proteins that alter in hepatotoxicity include hhrinogen, haptoglobin, transferrin, ceruloplasmin, alphaj-macroglobulin, coagulation cascade and complement proteins, secretory IgA, carbohydrate deficient transferrin (CDT), and protein F (see Chapter 8). 

C. G. Cochrane, H. J. Muller-Eberhard, and B. S. Aikin Depletion of plasma complement in vivo by a protein of cobra venom Its effects on various immunologic reactions. 1970. 7. Immunol. 105, 55-69. 

In passive immunotherapy immune globulin (Ig) is an effective replacement in most forms of antibody deficiency (14). In the past, plasma was used instead of immune globulin, but plasma is rarely indicated in the 1990s because of the risk of disease, particularly AIDS, transmission. Because plasma contains many factors in addition to immunoglobulins (Igs), plasma is, however, of particular value in patients with protein-losing enteropathy, complement deficiencies, and refractory diarrhea. 

Mediators derived from activated plasma protein cascades Complement system... 

The number of different proteins in a membrane varies from less than a dozen in the sarcoplasmic reticulum to over 100 in the plasma membrane. Most membrane proteins can be separated from one another using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), a technique that has revolutionized their study. In the absence of SDS, few membrane proteins would remain soluble during electrophoresis. Proteins are the major functional molecules of membranes and consist of enzymes, pumps and channels, structural components, antigens (eg, for histocompatibility), and receptors for various molecules. Because every membrane possesses a different complement of proteins, there is no such thing as a typical membrane structure. The enzymatic properties of several different membranes are shown in Table 41-2. 

Table 50-2 summarizes the functions of many of the plasma proteins. The remainder of the material in this chapter presents basic information regarding selected plasma proteins albumin, haptoglobin, transferrin, ceruloplasmin, aj-antitrypsin, aj i roglobulin, the immunoglobulins, and the complement system. The lipoproteins are discussed in Chapter 25. 

The Complement System Comprises About 20 Plasma Proteins Is Involved in Cell Lysis, Inflammation, Other Processes... 

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