T cell epitopes are leukocytes of the lymphatic system in the human body and are related specifically to the autoimmune functions of the lymphatic system. They are sometimes described as being an antigenic determinant, are lymphocytes and are grouped in white blood cells. The T cell epitope has its origin in the bone marrow as B cells do, but it more fully develops in the thymus, which is situated just above the heart. There are many versions of these epitopes, and they all have their specific function. T cell epitopes have been the focus of medical studies for their use in developing vaccines and treatments for a variety of major illnesses and diseases, some of which are genetically inherited.
Some of the T cells are known as cytotoxic T cells and function by attacking viruses that invade the body, and others have been studied to develop treatments to attack tumor cells. These "natural killer" T cells have been used to attack not only tumor cells, but also the cells produced by the herpes virus. Some T cell epitopes, called regulatory T cells, shut down the antiimmune responses of a body at the end of an immune reaction and thus keep a body from attacking healthy cells after the trigger and illness has expired. They thus regulate the functions of T cells throughout an immune reaction.
Many scientific studies have been done trying to isolate T cell epitopes with antigen presenting cells to combat pathogens and develop vaccines. This is difficult, however, because pathogens mutate quickly, and it is difficult to develop vaccines quickly enough before these mutations take place and render the vaccine less effective. T cell epitopes are the only hope where vaccines are not available in some diseases as yet, so they are still isolated and used as treatments for tuburculosis; childhood acute lymphoblastic leukemia; the genetic condition known as celiac disease, specifically with gluten sensitivities; and in treatments of human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) treatments.
Additionally, T cell epitopes have been studied to find a vaccine for malaria. The malaria treatment vaccine studies, however, have found difficulties. Malaria differs from region to region because the mosquitoes that pass the pathogen mutate the pathogen through contamination from biting those who have suffered more than one malaria infestation previously, and this causes further mutations to the pathogen. It is believed that the studies in Peru, Sierra Leone, Gambia, Vietnam and Iran on malaria vaccine prerequisites will one day make use of the functions of the T cell epitopes to stem the tide of deaths and debilitation from this disease.
One of the main events caused by AIDS is that patients lose their cluster of differentiation 4 (CD4) T cell epitopes and are left vulnerable and defenseless against many diseases. The human immunodeficiency virus attacks these CD4 T cells and kills them off one by one. Part of the reason for this is that when cluster of differentiation 8 (CD8) T cells detect that a CD4 cell is infected, it kills it off. When the count of CD4 cells falls below a count of 400 per microliter of blood in the body, the body is rendered nearly defenseless and can then fall prey to other viruses and fungi that reside within the human body but usually are kept at bay by a healthy immune system. Made up of chains of amino acids, these T cell epitopes are of incalculable assistance in the body’s fight against disease.