Study On The Effect Of Specific Membrane Protein Modification To Promote The Phagocytic Function Of Macrophages

Chimeric antigen receptor T(CAR-T)cell are genetically engineered T cell,which usually express chimeric antigen receptor that can recognize specific tumor antigens and then activate the immune system to eliminate tumors.These modified T cells are amplified and then infused to the donor patient.CAR-T therapy with the B cell lineage differentiation antigen CD19 as the therapeutic target is currently the most mature and effective treatment method in the treatment of hematological malignancies.Although CAR-T cells have been used in clinical,many problems still need to be solved,such as the suitable carrier,long-term safety,and how to effectively reach the inside of solid tumors.Macrophages are an important group of immune cells which are involved in tissue defense and homeostasis maintenance in the body.On the one hand,they can stimulate an adaptive immune response;on the other hand,they can use phagocytosis to eliminate pathogens,cells debris,damaged tissues,and even swallow entire tumor cells.Chimeric antigen receptors(CAR)are synthetic receptors that program T cells to kill cancer.The success of CAR-T cell therapy in the past few years has highlighted the prospects for programming immune cells,which gives us enlightenment,modification of membrane proteins on other immune cells might also achieve the effect of inhibiting tumor growth.In addition,compared with T cells,macrophages had unique advantages as a new carrier of cellular immunotherapy since they possess the strong infiltration and immune microenvironment regulation functions.Here,we designed a specific membrane protein modification molecule to promote the phagocytic function of macrophages,and we call the modified macrophages as modified MΦ.Macrophages modified by this specific membrane protein molecule could engulf specific targets including cancer cells.The specific membrane protein molecule was composed of different fragments,the antibody fragment in this topic is anti-HER2,which modified macrophages to promote their specific ability to target HER2~+tumor cells.By screening a set of phagocytic receptor intracellular domains,we found one of which cytoplasmic domain from a receptor could enhance the phagocytic ability of macrophages,and this domain was independent of its natural extracellular domain.Our data showed that in the in vitro co-culture model,modified MΦcould effectively phagocytose tumor cells,and in the mouse model,it could significantly inhibit tumor growth.In addition,we tried to design and synthesize a liposome in order to effectively transfect into the macrophages.The results showed that the transfection rate of the liposome could be60%-80%,but it could not transfect tumor cells by using the liposome.This might provide new treatment methods for targeting macrophage in vivo therapy.