Writer: Efe Sakarya
Cancer is one of the three top causes of mortality in developed countries. Cancer is predicted to become the most prevalent deadly illness in these countries as infectious disease medicines and cardiovascular disease prevention improve and life expectancy rises. Cancer is created by the steady proliferation of a single altered cell's offspring. In terms of the factors that contribute to the development of this lethal disorder in humans, recently increased GMO consumption, ozone layer depletion, and other similar environmental and ecological events are all contributors to tumor formation. To cure cancer, all malignant cells must be removed or killed without killing the patient. An appealing approach would be to stimulate an immune response against the tumor that distinguishes between tumor cells and their normal cell counterparts. Immunological methods for cancer therapy have been explored for over a century, with promising but unsustainable outcomes. Animal experiments, on the other hand, have revealed data for immune responses to tumors and demonstrated that T cells are a significant modulator of tumor immunity. Recent breakthroughs in our understanding of antigen presentation and the molecules involved in T-cell activation have led to the creation of new immunotherapeutic techniques that rely on a better molecular understanding of the immune response. These have shown promise in lab animals and are currently being evaluated in human patients. Before the discovery of the T-cells and their relationship with the cancer cells, there was no logical explanation for why the cancer cells could not be detected by the immune system of the body to be removed and destroyed.
T Cells and Their Roles in the Human Body
The establishment and maintenance of immune responses, homeostasis, and memory depend on T cells. They can differentiate between antigens from pathogens, tumors, and extracellular substances. In a living organism, T cells' underlying mechanisms have led to the development of immune-based cures and immunotherapies. T lymphocytes originate from bone marrow progenitors that migrate to the thymus, a small gland in the lymphatic system that makes and trains special white blood cells called T cells, for various reasons. There are two types of subsets of T cells: naive T cells and memory T cells. Naive T cells can respond to novel antigens in the body, while memory T cells, which are derived from pro-antigen activation, maintain long-term immunity. Further, T cells may act erratically when exposed to external stimuli such as radiation or malignant stimuli.The effects of outer-body impacts must not be overlooked.
As is known, humans have a very long lifespan compared to most living beings in the environment. Therefore, T cells play an important role in keeping the lifespan of humans so long. However, in different stages of human life, T cell activities repeatedly change and evolve, and thus their functionality shifts completely. As we mentioned in one of the previous lines, there are two types of subsets of T cells, and their aspects are unique.
Early childhood (Infancy)
Since the human child is in the newborn phase, most of the T cells in the body are in the naive form of the two subsets. These T cells of immunity emerge from the thymus, with Treg cells also significantly represented. The highly accumulated encounters with newly formed and created antigens are at their peak during this stage of human life, and naive T cells play a significant role in fending off pathogens. In addition, Treg cells are critical for developing tolerance to innocuous and ubiquitous antigens, and long-term reserves of memory T cells are established. As predicted, the roles of memory T cells are lower compared to the naive cells at this exact stage experienced by humans, but the change in T cell predominance from naive to memory after childhood and the relative stability of immunity over decades of adulthood suggest changing roles for T cells in adults compared to children.
After a certain number of years, the number of new antigens encountered decreases in proportion to the number of years lived. As previously stated, T cell predominance from naive to memory beyond childhood, as well as stronger immune stability through decades of maturity, imply that T cells have distinct tasks in adults than in children. Rather than developing tolerance, T cells' job at this stage of human development is to maintain homeostasis and immunoregulation in the face of repeatedly and persistently encountered antigens. The numbers of the two types of T cell subsets—naive and memory—are roughly the same and function similarly.
The senile stage is the final stage in the framework of the broad categorization of the human life span. There are well-documented immunosenescence alterations in this last stage, including increased inflammation and a reduction in T cell functioning, which contribute to immunological dysregulation and associated disease. Additionally, the body is more open to outer stimuli that may try to get into the body, which is already weak in terms of immunity. At those times, environmental factors, including but not limited to ozone layer depletion caused by increased NO, SO, and CO, genetically modified organisms (GMO) consumption, and so forth, have their highest influences on the individual. In conclusion, both biological and environmental factors can reduce one's T cell functionality capacity by interfering with its overall formation.
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