Abstract: The present invention relates to an artificial antigen-presenting cell prepared from an HLA-null cell line by using a multiplex CRISPR-Cas9 system and the use thereof and, more particularly, to a novel artificial antigen-presenting cell which includes the ability to present antigens of HLA class I and a co-stimulatory molecule group transferred from an HLA-A, -B, -C null cell line generated using a multiplex CRISPR-Cas9 system and to stimulate T cells, an immunotherapeutic agent using the same, and the use thereof for treating tumors, pathogenic infections, and autoimmune diseases.