Advances in cancer treatment are evolving from surgery and chemotherapy to immunotherapy. Antitumor immunotherapy using immune surveillance and CTLs is gaining attention as an innovative way to selectively eliminate cancer cells with minimal damage to normal cells.
The fear of cancer and efforts to overcome it have been a constant in human history, both in the East and the West. Cancer comes in many forms, and its treatment methods have evolved steadily. In the past, the lack of understanding of cancer made it nearly impossible to treat, but modern medicine has made incredible advances. In the early days, surgical removal of tumors was the main approach, but nowadays, more sophisticated techniques are being used to treat cancer.
At the current state of the art, surgery is often unable to remove cancer cells that have spread too far, so chemotherapy or radiation is often resorted to. However, these treatments have the limitation of attacking not only cancer cells but also normal cells. By targeting rapidly dividing cells, these treatments have the side effect of weakening or destroying normal rapidly dividing cells, such as bone marrow cells and hair roots. This can cause patients to experience serious side effects, including decreased stamina, hair loss, and weakened immunity.
To address these issues, developing anticancer therapies that accurately target and destroy only cancer cells is currently a major challenge for the immunology community. In the process, we are exploring ways to better harness the power of our naturally occurring immune system. The body’s immune system is responsible for detecting and eliminating abnormal cells or foreign invaders, a process known as immune surveillance. Immune surveillance is responsible for recognizing and eliminating not only foreign invaders, but also mutated cells that express new antigens, such as cancer cells. However, cancer cells proliferate and transform very rapidly, allowing them to grow beyond the limits of the immune system.
Tumor immunologists are therefore working to harness the antitumor immune response as the next generation of anti-cancer drugs. Immunotherapy, which selectively eliminates cancer cells, has attracted significant attention because, unlike conventional treatments, it can minimize damage to normal cells.
The antitumor immune response is primarily mediated by T cells. Once T cells are activated to recognize tumor antigens expressed on tumor cells, CD4+ T cells and CD8+ T cells take over the role of recognizing and attacking tumor cells. In particular, CD8+ T cells play an important role in the direct elimination of tumor cells by differentiating into tumor-specific cytolytic T lymphocytes (CTLs). The role of antigen-presenting cells (APCs) is crucial for the formation of these CTLs, and recent studies have highlighted dendritic cells (DCs) as the most potent antigen-presenting cells.
Prof. Thomas Brocker and colleagues at Ludwig-Maximilian University in Germany have found that DCs play an important role in activating CTLs responses. DCs are highly effective at phagocytosing antigens on tumor cells and presenting them to T cells to induce CTLs responses. These findings are expected to contribute significantly to the development of antitumor immunotherapy in the future.
Unlike conventional chemotherapy or radiotherapy, immune surveillance and CTLs are very innovative in that they can target only cancer cells to maximize the effectiveness of treatment. In addition, Tumor Immunotherapy, which is being studied in recent years, can be divided into three main categories: passive immunity, active immunity, and immune enhancement.
Passive immunization involves infusing patients with already activated T lymphocytes or antibodies. This method directly boosts the patient’s immune system to attack the cancer cells. Recently, researchers have also been working on using the patient’s own T lymphocytes, which are cultured and re-infused. Active immunization involves inducing an immune response by administering a vaccine containing antigens to the patient, which is also being studied. In addition, immune-boosting therapies inhibit the ability of cancer cells to evade the immune system and promote immune responses to effectively eliminate cancer.
This makes immune surveillance and therapies utilizing CTLs an important area of research to overcome the limitations of conventional cancer treatment. In this article, we have reviewed the various features and principles of antitumor immunity and tumor immunotherapy that have gained attention in recent years. While these therapies are still in the research phase, current findings hold promise for future cancer treatments.
In the future, it is expected that these immunotherapies will be further developed to minimize side effects and effectively treat cancer. Cancer will continue to be a constant challenge for mankind, and one day we may be able to overcome it once and for all.
