Brain-derived neurotrophic factor, also known as BDNF, is a member of the neurotrophin family of growth factors, which are related to the canonical Nerve Growth Factor. BDNF acts on certain neurons of the central nervous system and the peripheral nervous system, helping to support the survival of existing neurons, and encourage the growth and differentiation of new neurons and synapses. Besides, Sortilin 1 (SORT1) has been identified as an interactor of BDNF, thus a binding ELISA assay was conducted to detect the interaction of recombinant human BDNF and recombinant human SORT1. Briefly, SORT1 were diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100μl were then transferred to BDNF-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-SORT1 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50µL stop solution to the wells and read at 450/630nm immediately. The binding activity of of BDNF and SORT1 was shown in Figure 1, and this effect was in a dose dependent manner.