October 20, 2021

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TILs Cell Therapy: An important hope to conquer tumors

TILs Cell Therapy: An important hope to conquer tumors

 

TILs Cell Therapy: An important hope to conquer tumors.  Cellular immunotherapy is hailed as an important hope for conquering tumors. Today, let’s talk about the TILs immune cell therapy.

Cellular immunotherapy is hailed as an important hope for conquering tumors. With the development of immunology, various immunotherapies against cancer cells have sprung up, starting from anti-immune checkpoint antibody drugs (the treatment methods are mostly small molecules against targets such as PD-1, PD-L1, and CTLA-4). Drugs and antibody drugs), to immune cell therapy (LAK, DC, CIK, DC-CIK, CAR-T, TCR-T, TILs and other therapies).

TILs Cell Therapy: An important hope to conquer tumors


Many cell therapies must be clear to everyone. Today, let’s take a look at what TILs immunotherapy is all about.

 

1 What are TILs cells

TILs (Tumor Infiltrating Lymphocytes) are a kind of infiltrating lymphocytes isolated from tumor tissues. Most of the tumor tissues removed by surgery are tumor cells, and a small part are lymphocytes.

Lymphocytes are a powerful army that kills cancer cells. However, due to tumor microenvironment and other reasons, T lymphocytes have limited functions, or cannot migrate to tumor tissues, or inhibit their activity in tumor tissues, and cannot kill cancer cells. Some of these lymphocytes are T cells that target tumor-specific mutant antigens. They are the most powerful immune cells that penetrate into the enemy’s interior and are considered to be a specific immune response of the body to tumor cells. Therefore, how to activate the fighting forces in the body and strengthen the “arm” of T cells so that they can fully exert their combat effectiveness in tumor tissues and attack tumor cells is one of the current hot spots in tumor research.


2 What is TILs cellular immunotherapy

TILs cell therapy refers to the separation of tumor-infiltrating lymphocytes from tumor tissues, culture in vitro and a large number of expansions, and then infusion into the patient’s body. The effector cells of TILs therapy are natural selection and enrichment, and the proportion of tumor-specific T cells is high and the population is rich in diversity. Compared with CAR-T cell therapy and PD-1/PD-L1 antibodies, it has multiple targets, It has the advantages of strong tumor tendency and infiltration capacity, and low side effects.

TILs Cell Therapy: An important hope to conquer tumors

The immune cells of TILs therapy are derived from tumor tissues, and their ability to recognize tumors is higher than that of immune cells derived from blood. This new type of therapy is not simply amplifying and reinfusing, but to identify specific mutations in the patient’s body, use the mutation information to find T cells that can effectively target these mutations, and then extract T cells. These T cells can accurately identify cancer cells. After a series of operations such as in vitro culture and expansion, the extracted T cells are re-infused into the patient’s body to exert anti-tumor effects.


3 TILs cell therapy and CAR-T cell therapy

At first glance, I feel that there is not much difference between TILs cell therapy and CAR-T cell therapy. In fact, there are still many differences between them.

First of all, CAR-T cell therapy and so on. Their T cells are derived from the blood, while the T cells in TILs immunotherapy are directly derived from infiltrating tumor tissue. What is the difference between the two?

We must know that the reason why tumor cells can grow unscrupulously is because they have a special mechanism to avoid the human immune system. These methods include but are not limited to: reducing the expression of recognition signals on the cell surface so that immune cells cannot recognize themselves. , Express PD-L1 to inhibit T cells, grab methionine from surrounding T cells, etc. Therefore, in general, the proportion of T cells in the blood that can recognize tumor cells is very low, while the ability of TILs to recognize tumor cells is much higher. .

Secondly, because the T cells extracted by CAR-T cell therapy and other methods have weak ability to recognize tumor cells, they generally need to be genetically modified, but the mechanism of specific recognition is very complicated, and gene editing technology often only allows The modified cells recognize cells with the same type of antigen, so there may be accidental injuries. However, TILs immunotherapy only needs to screen various lymphocytes without artificial modification. The selected T cells are more specific and have a lower possibility of accidental injury.

In addition, CAR-T cell therapy is only effective for leukemia, B-cell lymphoma and other cancers, but has little effect on solid tumors. The TILs therapy has an ideal effect on solid tumors.

 


4 Advantages of TILs cell therapy

It has strong specificity for tumors and can kill cancer cells in a targeted manner. The use of tumor-killing TIL lymphocytes for cancer immunotherapy has specificity, killing cancer cells in a targeted manner, and tumor lesions are significantly reduced. The targeted screening process ensures that only immune cells that recognize tumor cells are amplified.
After treatment, the recurrence rate is low and the anti-recurrence is strong. For the removal of residual tumor cells after surgery, for postoperative anti-recurrence and metastasis treatment, it is more effective in combination with radiotherapy and chemotherapy. The first survivor to receive TIL therapy has successfully lived a healthy life for 10 years.

Adapt to a variety of solid tumors. It has a wide range of indications and has obvious curative effect on primary tumors and metastases. Reinfusion after in vitro experiment has high safety, fewer reinfusion times and few side effects.

Cooperating with other drugs can achieve better results, and the strong combination will double the effect of killing cancer!
The immune-enhancing drugs IL-2 and PD-1 inhibitors can be used in combination to better exert the anti-cancer effect. IL-2 is interleukin-2, which can stimulate the proliferation of T cells and activate T cells. PD-1 is an immune checkpoint protein expressed on the surface of T cells. It can bind to the PD-L1 protein expressed on the surface of tumor cells to initiate a signal to inhibit the function of T cells and promote T cell apoptosis. PD-1 inhibitors can block the combination of PD-1 and PD-L1, relieve tumor cells’ immune suppression of T cells, and allow T cells to better kill tumor cells.

 

5 Problems with TILs therapy

TILs therapy is currently only in clinical trials. As a highly differentiated, customized and targeted immunotherapy, TILs therapy still has certain limitations in terms of effectiveness, safety and accessibility. For example, it is very difficult to isolate specific T cells from infiltrating tumor tissues, and a unified and standardized program has not yet been formed; furthermore, there is no solution to the problem of T cells being inhibited by the tumor microenvironment and so on.

 

All in all, as a new type of immunotherapy, it will bring huge survival benefits to cancer patients. In the treatment of solid tumors, TILs therapy has made breakthrough progress, whether used alone or in combination with other treatment methods or drugs, and has produced gratifying curative effects in a variety of cancer types. TILs have become the focus of attention in the global biomedicine field, whether from basic research to process optimization, or from the expansion of indications to multi-scheme combination.

 

 

 

 

(source:internet, reference only)


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