Fig. 2.

(A) ¹⁵N HSQC spectra of 100 μM ¹⁵N mAβ42 alone (blue) and with 100 μM sTREM2 (red). (B) ¹⁵N HSQC spectra of 100 μM ¹⁵N mAβ40 alone (blue) and with 100 μM sTREM2 (red). (C) A cosedimentation assay to quantify sTREM2/fibrillar Aβ42 binding by incubating sTREM2 (10 nM) with various concentrations of fibrillar Aβ42. Quantification of fibril-bound sTREM2 using Western blot probed by anti–His-HRP conjugate antibody. (D) A binding curve obtained by fitting the data to a saturation binding model. The apparent binding constant is 2.6 ± 0.3 μM. (E) A cosedimentation assay to quantify sTREM2 and fibrillar Aβ40 binding by incubating 10 nM sTREM2 with various concentrations of fibrillar Aβ40. The Western blot was stained using anti–His-HRP conjugate antibody. (F) A binding curve obtained by fitting the data to a saturation binding model. The apparent binding constant for sTREM2 to Aβ40 is 2.3 ± 0.4 μM.