Figure 1. ELISA of Aβ₄₀ and Aβ₄₂ peptides from conditioned media of SH-SY5Y cells overexpressing C99.

Aβ₄₀ and Aβ₄₂ were measured by ELISA. C99 was intracellularly cleaved, generating different amounts of Aβ₄₂ and Aβ₄₀ in C99WT, C99I45F and C99V50F. As was expected [4], [5], C99I45F transfected cells generated large amounts of Aβ₄₂ and low levels of Aβ₄₀ resulting in a large Aβ₄₂/Aβ₄₀ ratio, whereas the opposite regulation pattern was detected for C99V50F transfected cells. Mock-transfected cells only produced very low (endogenous) levels of Aβ₄₂ and Aβ₄₀, hence, their Aβ levels were not detectable, because they were close to the detection limit of the ELISA.