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Researchers have found that T Cells can target cells that are in a state of cellular senescence, without damaging the tissues while promoting a longer life span. 

When a cell is in a state of cycle arrest and is stable in that cycle, it is considered cellular senescence. Senescent cells do not respond to growth-promoting signaling or stimuli and exhibit various biochemical changes leading to a phenotype characterized by altered gene expression and changes in cellular metabolism. The biological role of senescence is multifaceted and is important during embryonic development and wound healing. However, it is also involved in pathological processes such as cancer development and chronic inflammatory conditions.

The University of Oxford conducted clinical trials on a possible vaccine for SARS-CoV-2 and the results produce a positive immune response. 

As the race for a COVID (SARS-CoV-2) vaccine forges ahead across the globe, some scientists are obtaining clinical trial results that suggest progress toward an effective vaccine. Results of clinical trials conducted by scientists at the University of Oxford suggest that their newly developed vaccine elicits expected immune responses with an acceptable safety profile. Two immunity responses, antibody production, and T cell response to infected cells were assessed in the clinical trial participants.

New studies have found that people who have tested negative for COVID-19 antibodies, developed T cells instead in a response to their COVID-19 infections. 

When the body is infected with a pathogen such as a virus, it mounts a protective response through immune cells and the production of pathogen-specific antibodies. The antibodies remove the viruses before they can infect cells. Cytotoxic T cells kill infected cells via inflammatory mediators to prevent the function of the invading organism. In the case of COVID-19 (SARS-CoV-2) clinical studies, patients have been found to recover from the viral infection without the development of antibodies to the virus. However, they did develop a T-cell response to COVID-19. Therefore, it is believed that people who are asymptomatic or have a mild illness can remove the virus via T cells.

Cincinnati Children’s hospital laboratory led a study that discovered a possible treatment for autoimmune diseases using T cells and CAR NK-cells. 

Adaptive or acquired immunity is a specific response to pathogens. An important aspect of adaptive immunity and memory is the T-cell help to B cells. The support to B cells is provided by follicular helper CD4 T cells and entails helping B cells to produce antibodies against invading pathogens. Although follicular helper T cells are needed for long-term immunity, exaggerated responses of these T cells can lead to adverse reactions, including the promotion of autoimmune reactions.

A recent Phase I trial studying the effect of TIL therapy on lung cancer shows promising results for long-term patient remission.

Tumor-infiltrating lymphocytes (TILs) are T-cells that infiltrate solid tumors to attack tumor antigens. Still, the tumor microenvironment inhibits T-cell growth leading to low numbers of the cells and insufficient immune response. Checkpoint proteins on tumor surfaces, such as PD-1, can also further inhibit T-cell response in tumors. However, in the case of melanoma, scientists have been able to achieve a complete remission with TILs that can last over a decade.