Establishment and characterization of a mouse tumor cell line with irreversible downregulation of MHC class I molecules.

In the majority of human tumors, downregulation of major histocompatibility complex class I (MHC‑I) expression contributes to the escape from the host immune system and resistance to immunotherapy. Relevant animal models are therefore needed to enhance the efficacy of cancer immunotherapy. As loss of β‑2 microglobulin expression results in irreversible downregulation of surface MHC‑I molecules in various human tumors, the β‑2 microglobulin gene (B2m) was deactivated in a mouse oncogenic TC‑1 cell line and a TC‑1/dB2m cell line that was negative for surface MHC‑I expression was derived.