Figure 3: Detection of amyloid seeding activity in FPE retropharyngeal lymph node.
(a) Immunohistochemistry of retropharyngeal lymph nodes from three terminal white-tailed deer. Mild to marked PrPCWD immunoreactivity is present in germinal centers of lymphoid follicles. No PrPCWD immunoreactivity is detected in negative control animals. All IHC images are 200× magnification, measurement bars represent 20 μ m. (b) RT-QuIC of serial dilutions of terminal-disease, IHC positive FPE retropharyngeal lymph node and 10% frozen homogenate. Similar to obex samples (see Fig. 2), RT-QuIC successfully detected amyloid seeding activity in FPE retropharyngeal lymph node samples. The range of detection was similar between FPE samples and frozen samples, generally from 10−1 to 10−5. Spontaneous amyloid formation was rare in negative controls and did not differ between FPE and frozen samples. Each point represents median and IQR and is derived of 8 replicates from a minimum of two separate experiments.
