Development and validation of ELISA method for detection of human signal regulatory protein α-anti-CD20 mouse chimeric antibody fusion protein IMM0306 in human serum

IMM0306 is a recombinant human signal regulatory protein α-anti-CD20 mouse chimeric antibody fusion protein, intended to treat refractory or recurrent CD20 positive B-cell non-Hodgkin lymphoma (B-NHL) in clinical. In this study, an ELISA method was established to evaluate the pharmacokinetics of IMM0306 in human serum. The experiment was approved by the Ethics Committee of the Cancer Hospital of the Chinese Academy of Medical Sciences (No. CTR20192612). Recombinant human CD47 protein was coated with the plate overnight, blocking the plate with 5% skin milk for 2 h. After washing, 100 μL per well standard and unknown samples were added, and incubated for 1.5 h. After washing, the detection antibody Anti-IMM0306-Biotin was added and incubated for 1 h, and then HRP-labeled streptavidin was added for 1 h, and the color was detected. The optimal concentration of coating reagent was 2 μg·mL^-1 by ELISA method, and the optimal dilution of anti-IMM0306-biotin and SA-HRP were 1:500 and 1:5 000, respectively. The lower limit of quantitation was 4 ng·mL^-1, and the standard curve range was 4-100 ng·mL^-1. The verification results of the method meets the corresponding acceptance criteria, and can be used in IMM0306 clinical pharmacokinetic studies.