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. 2019 Jan 10;67(4):275–289. doi: 10.1369/0022155418824092

Figure 6.

Figure 6.

Graphical representation of stain intensity (y-axis) after immunostaining with the HER2 SP3 immunostain. Panel A shows that the loss of immunoreactivity after exposure to formaldehyde only occurs if the ivDde blocking group is removed. In Panel A, stain intensity of the ivDde-blocked peptide (“ivDde+”) is compared with the same peptide after regeneration of the epsilon amine (“Amine”). Each peptide (ivDde+ and Amine) was tested after formaldehyde fixation (“Fixed”) or without formaldehyde fixation (“Unfixed”). Each experimental group was stained with (blue) or without (orange) HIER. In Panel A, all of the peptides were at a concentration of 1,396,145 peptide epitopes per microbead. In Panel B, we examine the effect of various peptide concentration on HER2 SP3 immunostain intensity. In Panel B, all three groups (at various peptide concentrations) are formaldehyde-fixed and are after regeneration of the epsilon amine. The group to the far left (1,396,145) is under the same conditions as the group to the far right in Panel A. The data represent the mean ± SD of triplicate slides. Abbreviations: HIER, heat-induced epitope retrieval; HER2, human epidermal growth factor receptor 2.