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A.S. Schelpe et al.
typic antibodies developed against anti-spacer autoanti- body II-1 (17H9) and I-9 (7D10) recognized shared or unique idiotopes in II-1 and I-9. As a control, we included the anti-idiotypic antibody 9G12 developed against the anti-spacer autoantibody TTP73, which does not have an overlapping epitope with II-1 and I-9.
The anti-idiotypic antibody against anti-spacer autoan- tibody II-1 (17H9) recognized a unique idiotope in II-1 as it only captured II-1 and not anti-spacer autoantibodies I- 9 and TTP73 (Figure 3A). As expected, the anti-idiotypic antibody against TTP73 (9G12) also recognized a unique idiotope in anti-spacer autoantibody TTP73 as it only cap- tured TTP73 and not anti-spacer autoantibodies II-1 and I- 9 (Figure 3B). In contrast, the anti-idiotypic antibody (7D10) against the anti-spacer I-9 idiotope captured both anti-spacer autoantibody I-9 and II-1 (Figure 3C) showing
A
that anti-idiotypic antibody 7D10 recognizes a common idiotope in II-1 and I-9.
In conclusion, these data show that the anti-idiotypic antibodies against anti-spacer autoantibody II-1 (17H9) and TTP73 (9G12) recognize a unique idiotope in II-1 and TTP73, respectively, whereas the anti-idiotypic antibody developed against anti-spacer autoantibody I-9 (7D10) recognizes an idiotope present in both anti-spacer autoan- tibodies II-1 and I-9 (Figure 3).
Identification of anti-spacer idiotope profiles in plasmas of acute iTTP patients using the newly developed anti-idiotypic antibodies
As a first step, we screened the plasma of 151 iTTP patients for the presence or absence of the anti-spacer II-
B
C
Figure 3. Anti-idiotypic antibodies and their binding to the anti-spac- er idiotopes of II-1, TTP73 and I-9. Binding of human anti-spacer autoantibodies (autoAbs) II-1 (red), TTP73 (green), I-9 (orange) and of a pool of human IgG anti- bodies (negative control, black) to coated murine anti-idiotypic anti- body (Ab) 17H9 developed against II-1 (A), 9G12 developed against TTP73 (B) and 7D10 developed against I-9 (C). Bound human anti- spacer autoantibodies II-1, TTP73 and I-9 were detected using a anti- human IgG1-4. Data are expressed as relative absorbance values (mean+Standard Deviation, n=3) [da sottolineare il simbolo +]with absorbance of binding of II-1, TTP73 and I-9 at 1 μg/mL to their respective anti-idiotypic antibod- ies set as 1. OD: optical density.
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haematologica | 2019; 104(6)