Background: The specific Intravenous Immunoglobulin (IVIG) for Alzheimer’s Disease
(AD) is developing, which contains a high level of naturally occurring autoantibodies against amyloid-β
(nAbs-Aβ), and the measure of nAbs-Aβ content is greatly essential. Though Enzyme-Linked Immunosorbent
Assay (ELISA) has been widely used in detecting the nAbs-Aβ content, the impact of Aβ aggregates
species chosen as antigen in ELISA on this measure has not been evaluated.
Objective: To clarify the influence of different Aβ40/42 aggregates as antigen during ELISA on the content
of nAbs-Aβ40/42 measured in IVIG.
Method: Preparation of various Aβ40/42 aggregates was performed by different aggregation solutions and
various lengths of time, and analyzed by western blot. Different Aβ40/42 aggregates as antigen were
adopted to measure the nAbs-Aβ40/42 content in IVIG by ELISA, and the control was carried out to reduce
interference of nonspecific binding. The Bonferroni and Dunnett’s T3 were used
for statistical analysis.
Results: The duration for the formation of Aβ40/42 aggregates had more effect on detecting nAbs-Aβ40/42
content in IVIG than the aggregation solution. Higher content of nAbs-Aβ40/42 in the same IVIG was
displayed when measured with Aβ40/42 aggregates at day 3, instead of at day 0.5 and day 7.0. The nAbs-
Aβ40/42 contents in the same IVIG measured with Aβ40/42 aggregates prepared in different solutions were
obviously different, but there was no significant regularity among them.
Conclusion: The nAbs-Aβ40/42 content in the same IVIG is significantly different when measured with
Aβ40/42 aggregated under different conditions. The nAbs-Aβ40/42 content in IVIG by antigen-dependent
measures, like ELISA, is uncertain.