The immune system: genes, receptors, signals : [proceedings] / edited by Eli E. Sercarz, Alan R. Williamson [and] C. Fred Fox.

  • ICN-UCLA Symposium on Molecular Biology
Date:
1974
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The immune system: genes, receptors, signals : [proceedings] / edited by Eli E. Sercarz, Alan R. Williamson [and] C. Fred Fox. Source: Wellcome Collection.

    59/664 (page 31)
    THE IMMUNE SYSTEM availability of antibody preparations which could be frac¬ tionated by elution with a homologous series of structuraly related ligands raised the question to what extent kinetic parameters of these different fractions may be correlated with the structure of the ligands and with the nature of the eluate. Two systems have been studied until now: The dyna¬ mics interaction of 1-(m-nitrophenyl) Flavazoles of isomal- tose oligosaccharides with purified antidextran antibodies (28) and more extensively those of l-(dansyl) ethane di¬ amine derivatives of oligoalanines with antipolyalanine fractions (15). The interaction of the haptens with the antibody binding sites were followed by measuring the fluor¬ escent energy transfer from the excited protein tryptophanes to the dansyl side chain attached to the alanine hapten. In figure 5 the fluorometric titration of the ala2 eluate of antipolyalanine HSA with the D-ala-diaminoethane-dansyl ligand, is illustrated. The protein emission is quenched upon binding whereas the emission of the dansyl bound by virtue of the D-ala residue is increasing. Table 4 summa¬ rizes the data obtained in collaboration with Mr. Arie Licht on this system. The variation in both specific rates do not show the same trend for the two eluates. Moreover, their variation is limited to a range of less than an order of magnitude. It is, however, interesting that the rates of binding (k]^2) within one to two orders of magnitude slower than those observed for the kj^2 values of the binding of DNP ligands to heterogeneous anti DNP antibodies (4,5). The specific rates of dissociation are within the range found in most other cases. The reason for the intriguingly slow rate of binding of these haptens is unclear and may have to do with the different chemical nature of the oligo- alanine hapten as compared with DNP. ACKNOWLEDGMENT The studies reported in this paper have been supported by a research grant from the Volkswagenwerk foundation which is gratefully acknowledged. 31