What Is Cell Therapy?

Somatic cell therapy is a method of treating the body cells in vitro and then returning them to the patient.

Somatic cell therapy

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Somatic cell therapy is a method of treating the body cells in vitro and then returning them to the patient.

Somatic cell therapy

Somatic cell therapy is a method of treating the body cells in vitro and then returning them to the patient. At present, somatic cell therapy is mainly based on autologous somatic cell therapy, which is divided into active specific immunotherapy and passive immunotherapy.

Active specific immunotherapy, commonly known as tumor vaccine technology, uses tumor cells or their extracts to immunize cancer patients. It is essentially a physiological treatment that can specifically stimulate and enhance the body's active immunity to tumor Rejection, to achieve the purpose of radical tumor treatment. At present, the main problem is that tumor cells are derived from normal cells. Compared with normal cells, the specific antigen molecules or related antigen molecules of tumor cells are only a change in number or a slight change in structure. Tumor cells are rejected as "foreign foreign bodies". In recent years, with the development of immunology, tumor immunology theory and bioengineering technology, new developments have been made in tumor vaccine technology. Among them, dendritic cell (DC) technology is a very attractive treatment.

DC is an important full-time antigen-presenting cell for human uptake, processing, and presentation of antigens. DC cannot directly kill tumor cells, but it can significantly stimulate the proliferation of naive T cells and play an important role in regulating cellular and humoral immunity of the body. The mononuclear cells in the patient's peripheral blood are used for in vitro culture and expansion, and are returned to the patient to activate the patient's immune system, thereby killing and limiting tumor cells. DC therapy has achieved encouraging results in the treatment of various tumors including melanoma, renal cell carcinoma, ovarian cancer, lymphoma, bowel cancer, bladder cancer, liver cancer and other tumors. The center has also started treatments for melanoma and renal cell carcinoma since 2002, and DC treatments for other types of tumors are also being explored.

Adoptive immunotherapy is mainly based on infusion of specific or non-specific tumor killer cells, which can not only correct the low cellular immune function, but also directly exert anti-tumor effects. The infused cells mainly include lymphokine-activated killer cells (LAK cells), tumor infiltrating lymphocytes (TIL cells), and cytotoxic T cells (CTL). LAK cells are isolated from lymphocytes from peripheral venous blood and formed after 35 days of culture in vitro with a culture medium rich in IL-2 (1000-2000 U / ml). TIL cells are isolated and purified lymphocytes from resected tumor tissue or cancerous thoracic and ascites fluid. TIL cells are currently considered to have higher killing activity on tumor cells than LAK cells. CTL cells are co-cultured and induced by tumor cells treated with mitomycin as a stimulating cell and a small amount of IL-2 in peripheral blood lymphocytes of patients. This process has complicated procedures, many influencing factors, easy contamination, and the efficacy is not better than LAK cells, so it is rarely carried out at present. LAK therapy is currently used more often. That is, a certain amount of IL-2 / LAK should be infused at the same time as infusion of cells to ensure the efficacy. LAK cell surface markers are characterized as non-MHC restricted killer cells. LAK cells were collected from peripheral blood lymphocytes when patients rebounded a few days after starting IL-2 treatment. After being cultured with IL-2 for several days in vitro, it developed into highly non-specific cytotoxic cells before being returned to patients. LAK cells can not only directly attack tumor cells, but also secrete cytokines such as TNF and IFN, thereby aggravating tumor cell damage. Foreign literature reports that the use of IL-2 / LAK to treat renal cell carcinoma has an effective rate of 35%, melanoma, effective rate of 24%, non-Hodgkin's lymphoma, colorectal, rectal, bladder, liver, and cancerous ascites The effective rate is between 22% and 55%. Domestic Han Demin reported that 10 cases of laryngeal cancer were treated with the IL-2 / LAK method. The results were remission in 6 cases, mild remission in 3 cases, and ineffective in 1 case. In 1996, the Department of Hematology, Beijing Friendship Hospital [7] used IL-2 / LAK method to treat 20 tumor patients, and its various immune indicators were significantly improved, and the body's immune function was restored. LAK cells are mainly used clinically for systemic metastatic tumors (intravenous infusion of LAK cells + IL-2 shock therapy) and cancerous pleural effusion, head and neck cancer, liver cancer, bladder cancer, etc. In addition, LAK cells have achieved certain effects in post-transplantation lymphoproliferative diseases (PTLD).

TILs are T lymphocytes isolated directly from tumor tissues.

Induced by IL-2. With tumor-specific killing activity, especially effective for melanoma. Earlier reports were more effective than using IL-2 alone (34% vs. 17%). But long-term data on repeatability and time to remission are lacking.

CIK cells (cytokine induced killer)-cytokine-induced killer cells, are non-specific killer cells that are cultured from human peripheral blood mononuclear cells in vitro through the action of multiple cytokines. The activity was significantly higher than that of LAK cells. Since it was first proposed by Schmidt Wolf et al. Of Stanford University in the United States, it has been continuously improved. At present, it has a positive effect in bone marrow purification and leukemia treatment of tumor patients, and clinical trials on some solid tumor patients have also obtained encouraging results.