Epitope density

Silva GA, Czeisler C, Niece KL et al (2004) Selective differentiation of neural progenitor cells by high-epitope density nanofibers. Science 303 1352-1355... 

Capture ELISA on selected oligomeric fractions of formalin-treated RNase A (see curves 3-7 in Fig. 15.9) also reveal that the plateau values increase with an increase in the number of cross-linked molecules in the fractions. This is due to an increasing proportion of bound epitopes per binding site or, in other words, epitope density on the surface. Thus, the nearly identical plateau values for the titration of native RNase A and formalin-treated unfractionated RNase A (curves 1 and 2 in Fig. 15.9) are fortuitous, being caused by the particular composition of oligomers present in the formalin-treated RNase A preparations that was analyzed. 

Fig. 15. Mixed copolymers were generated to examine the effect of changing the recognition epitope density for a biologically active series of carbohydrate-substituted polymers. Note n and m represent ratios of mannose and galactose residues, respectively.

Cairo CW, Gestwicki JE, Kanai M, KiessUng LL. Control of multivalent interactions by binding epitope density. J Am Chem Soc 2002 124 1615-1619. 

The influence of physicochemical properties of liposomes, such as charge density, membrane fluidity, and epitope density, on the immune response elicited by antigens has been extensively studied [37]. In addition to antigens, other immune stimulators that are amphoteric muramyl peptides or lipid-soluble compounds, such as monophosphoryl lipid A or muramyl tripeptidyl-phosphatidylethanolamine, can also be incorporated into liposomes to increase their adjuvant effect in eliciting immune responses [34]. 

However, simply the production of a hapten and then an antigen and presentation to the immune system does not necessarily mean that an immune response will occur. Other factors are important, such as the epitope density already mentioned. 

The resulting epitope density may depend on the number of lysine groups in the particular protein, and this will in turn affect the immunogenicity of the antigen. Trifluoroacyl adducts have been detected on the outer surface of hepatocytes, presumably as a result of the hapten-complex processing and delivery by MHC I, which is described above. The fact that the production of the trifluoroacetyl chloride is part of the major metabolic pathway and that the majority of patients produce trifluoroacylated proteins suggests that it is differences in the immune surveillance system or immune responsiveness, which determine which patients will succumb to the immunotoxic effect. 

No definitive study of the effects of protein carrier on response is available, and many carrier proteins have been used, including globulins, albumin, hemocyanin, thyroglobulin, and fibrinogen. The optimal number of haptens, or the epitope density, is also controversial, but a density of 8 to 25 haptens per bovine serum albumin molecule is probably optimal (12),... 

The maximum OD of any mAb depends on the epitope density on the sample attached to the wells. The maximum OD for the polyclonal serum may well be greater than that for any mAb screened (unlike the example shown in Table 10.). This depends, to a large extent, on the number of different epitopes ex-... 

Mitchell GF, Humphrey JH, Williamson AR (1972) B cell tolerance induced by polymeric antigens I. Comparison of the dose and epitope density requirements for inactivation of primed and unprimed B cells in vivo. Eur J Immunol 5 361 Mota I (1964) The mechanism of anaphylaxis I. Production and biological properties of mast cell sensitizing antibody. Immunology 7 681 Neftel KA Waelti M Spengler H Von Felten A Weitzman SA Buergi H de Week AL (1981) Neutropenia after penicillins Toxic or immune-mediated Klin Wochenschr 59 877... 

Silva, G.A., Czeisler, C., Niece, K.L., Beniash, E., Harrington, D.A., Kessler, J.A., Stupp, S.I., 2004. Selective differentiation of neural progenitor cells by high-epitope density nanofibers. Science 303 (5662), 1352-1355. 

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