Method for preparing recombinant protein

[0027] This example provides a method for producing CD89 protein, which mainly expresses CD89 protein by plasmid transfection into HEK293 cells. Among them, HEK293 cells came from Shanghai Mingjin Biotechnology Co., Ltd., and the corresponding recombinant protein particles were donated by Professor Jin Jing from Northwestern University. In this method, Lipofectamine 2000 transfection reagent was used to transfect the corresponding recombinant protein plasmid in advance, and the HEK293 monoclonal cell line stably expressing the target protein was obtained through G418 screening, and then frozen and stored in liquid nitrogen for future use.

[0028] figure 1 and figure 2 Respectively, the time flow of the growth stage and the production stage of the method of the present embodiment, refer to figure 1 and figure 2 , the specific steps of the method are as follows:

[0029] 1. Growth stage

[0030] 1. Cell recovery and scale-up culture

[0031] 1) Resuscitation of frozen cell

[0062] This example provides a method for producing recombinant human ACE2-Fc protein, in which the ACE2-Fc protein is mainly expressed by plasmid transfection into HEK293 cells. Among them, HEK293 cells come from Shanghai Mingjin Biotechnology Co., Ltd., and the corresponding recombinant protein plasmid is synthesized by GenScript Biotechnology Co., Ltd. (The sequences of the target gene human ACE2 and Fc tag used in the plasmid can be obtained from NCBI or related literature. ). In this method, Lipofectamine 2000 transfection reagent was used to transfect the corresponding recombinant protein plasmid in advance, and the HEK293 monoclonal cell line stably expressing the target protein was obtained through G418 screening, and then frozen and stored in liquid nitrogen for future use.

[0063] The specific steps of the method are as follows:

[0064] 1. Growth stage

[0065] 1) Resuscitation of frozen cells: Carefully take out the frozen cells in liquid nitrogen, quickly put them