Complement resistance

There are two major factors predisposing to resistance to monoclonal antibody therapy. One is a tumor-related factor such as antigen loss, complement resistance antigen expression, intrinsic resistance, or tumor burden. Besides tumor-related factors, growing evidence has indicated that patient-related factors may account for the different responses of the patients to monoclonal antibody therapy. For example, differences in ADCC or CDC function according to individuals may increase our understanding of... 

Pilzer, D., Gasser, 0., Moskovich, 0., Schifferli, J.A. and Fishelson, Z. (2005) Emission of membrane vesicles roles in complement resistance, immunity and cancer. Springer Semin. Immunopathol. 27, 375-387. 

Boel E, Bootsma H, de Kruif J, et al. (1998). Phage antibodies obtained by competitive selection on complement-resistant Moraxe/Za (Branhamella) catarrhalis recognize the high-molecular-weight outer membrane protein. Infect. Immun. 66 83-88. 

Saifuddin M, Parker CJ, Peeples ME, Gorny MK, Zolla-Pazner S, Ghassemi M, Rooney lA, Atkinson JP, Spear GT (1995) Role of virion-associated glycosylphosphatidylinositol-linked proteins CD55 and CD59 in complement resistance of cell line-derived and primary isolates of HIV-1. J Exp Med 182 501-509... 

Rather interestingly, protease-defident mutants of P. n vabs bind eater amounts of both C3b and C5b-9 and are ph ocytosed more readily, yet remain serum resistant. Recent data have shown that complement resistance in P.pnffvalis does not depend on protease production but requires expression of cell surface polysaccharide, which is an anionic branched mannan structure. Similarly, loss of Y.pestis Pla expression docs not affect resistance to human complement, although Pla-negative mutants show decreased virulence murine infection models. - " Complement deaving proteases may serve to limit anaphylatoxin generation and neutrophil influx rather than serving as the primary mechanism of serum resistance. 

Jarva H, Jokiranta TS, Wurzner R et al. Complement resistance mechanisms of streptococcL Mol Immunol 2003 40(2-4) 95-107. 

Other advantages bear repeating. These enzymes have been implicated in resistance to pathogens, and hence, their directed utilization against insects may complement resistance to pathogens. Three enzymes (PPO, POD, and LOX) have broad pH... 

The importance of the 08 antigen of E. coli((xl 3 linked trisaccharides of al- 2 linked D-mannose) was investigated in relation to serum complement resistance, by introducing the 08-polysaccharide determinants of a smooth form Hfr donor strain into its rough mutant recipient. The presence of the 08 antigen caused a delay in the bactericidal reaction, but did not fully protect the cell. It is clear that while the O-specific polysaccharides of E. coli and other Gram-negative bacteria can be important virulence factors, other determinants are necessary for the expression of full virulence. 

Huser A, Rudolph M, HofinarmC. Incorporation ofdeeay-acceleratinglactor into the bactrlovirrrs envelope generates complement-resistant gene trarrsfer vectors. Nat Bioteehnol 2001 19 451 55. 

Another useful element in imparting oxidation resistance to steel is silicon (complementing the effects of chromium). In the lower-chromium ranges, silicon in the amounts of 0.75 to 2 percent is more effective than chromium on a weight-percentage basis. The influence of 1 percent silicon in improving the oxidation rate of steels with varying chromium contents is shown in Fig. 28-26. 

Polymers with no pretence of high heat resistance but which complement the existing range of thermoplastics used mainly in light engineering application, e.g. phenoxies and aromatic polyesters. 

One method of overcoming some of the instability and loss in strength of oxychloride cements when exposed to water has been to modify them by impregnation with sulphur (Beaudoin, Ramachandran Feldman, 1977). The resulting material appears to be a composite in which the respective components complement each other. The magnesium oxychloride part has relatively poor resistance to water as initially formed, whereas the sulphur is difficult to wet and is completely insoluble in water. 

Figure 5.10. Protein complementation assay using murine DHFR. The F[l,2] and F[3] fragments are each fused to the homodimerizing GCN4 leucine zipper protein. A. Transformation of both Z-F[l,2] and Z-F[3] constructs results in reconstituted DHFR and growth of E. coh on agar plates containing trimethoprim. B. Transformation of Z-F[l,2] or Z-F[3] alone does not result in trimethoprim resistant E. coli cells. Figure adapted from Pelletier et al. (1998).

Nematode-host interactions are complex and poorly understood. The relationship between cyst nematodes and their hosts appears to have co-evolved, and as a result there are numerous genes for host resistance that are complemented by nematode parasitism genes (Triantaphyllou, 1987). Different alleles of these genes may interact in various combinations to give... 

A common characteristic of most CNS bacterial pathogens (e.g., H. influenzae, Escherichia coli, and N. meningitidis) is the presence of an extensive polysaccharide capsule that is resistant to neutrophil phagocytosis and complement opsonization. 

Petit, J.C., Resistance to listeriosis in mice that are deficient in the fifth component of complement, Infect. Immun., 27, 61, 1980. 

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