Epitope stability

Christie, J.F., Dunbar, B. and Kennedy, M.W. (1993) The ABA-1 allergen of the nematode Ascaris suum. epitope stability, mass spectrometry, and N-terminal sequence comparison with its homologue in Toxocara canis. Clinical and Experimental Immunology 92, 125-132. 

The following factors should be considered when choosing a staining method for a tissue cross-reactivity study (1) test article forms that are available, (2) test article affinity, (3) proposed plasma level for clinical studies, (4) epitope stability, and (5) ability to scale up the method to stain a large number of tissues. These various issues are addressed below. 

Antibody A52 with its epitope at residues 657-672 [129,139,274,275] inhibited the vanadate-induced crystallization of Ca " -ATPase and decreased the stability of preformed Ca " -ATPase crystals [285]. The vanadate-induced crystals arise by the association of the ATPase monomers into dimers (type A interaction), the dimers into dimer chains (type B interaction), and the dimer chains into 2-dimensional arrays (type C interaction). It is suggested that antibody A52 interferes with type B interactions, preventing the formation of dimer chains, without exerting major effect on the concentration of Ca -ATPase dimers in the membrane. The simplest interpretation of the destabilization of Ca -ATPase crystals by mAb A52 is that binding of the antibody to its antigenic site physically blocks the interaction between ATPase molecules [285]. Considering the large bulk of the antibody, such interference is not unexpected, yet only a few of the antibodies that bind to the Ca -ATPase in native sarcoplasmic reticulum interfered with crystallization. 

Hl-loop cation-binding sites can stabilize the flexible [14] a 1 helix designated as the thumb epitope, which is spatially close to the wrist epitope (Fig. 6d). This segment is found only among the TGF-b isoforms and the activins but not in other members of the TGF-b superfamily and may also participate in the recognition of type I receptor or other TGF-b activity regulation proteins, such as betaglycan. 

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