51黑料吃瓜网

T cells; Immune system; Adaptive immunity; Cytotoxic T cells; Helper T cells; Regulatory T cells; Memory T cells; Immunotherapy; Antigen recognition; CAR-T therapy

Introduction

The immune system is a complex network of cells and molecules designed to protect the body from infections and diseases. Among its key components, T cells stand out as central players in adaptive immunity. Unlike innate immune cells that provide immediate but non-specific responses, T cells offer a highly specialized and long-lasting immune response. These cells originate in the bone marrow and mature in the thymus, where they develop the ability to recognize foreign antigens while distinguishing them from self-antigens. The specificity of T cells enables precise targeting of infected or malignant cells, making them essential for immune surveillance and disease prevention. This paper delves into the diverse roles of T cells, their mechanisms of action, and their implications in immunotherapy.

Description

T cells can be classified into several subtypes, each with distinct functions

Helper T Cells (CD4+ T Cells) These cells coordinate immune responses by secreting cytokines that activate other immune cells, such as B cells and macrophages.

Cytotoxic T Cells (CD8+ T Cells) Responsible for directly killing virus-infected and cancerous cells by releasing perforins and granzymes.

Regulatory T Cells (Tregs) Suppress immune responses to prevent autoimmune reactions and maintain immune tolerance.

Memory T Cells Provide long-term immunity by “remembering” past infections and responding rapidly upon re-exposure to the same antigen.

Gamma delta (γδ) T Cells A unique subset with both innate and adaptive immune properties, involved in early immune responses.

Discussion

Activation and antigen recognition

T cells rely on antigen-presenting cells (APCs), such as dendritic cells, macrophages, and B cells, to recognize pathogens. The activation process involves

Antigen presentation Major Histocompatibility Complex (MHC) molecules present foreign antigens to T cells.

Co-stimulatory signals Additional molecular signals are required for full activation.

Clonal expansion Once activated, T cells proliferate and differentiate into effector cells that carry out immune functions.

Effector

Helper T Cells (Th1, Th2, Th17) Enhance immune responses by promoting inflammation, antibody production, and macrophage activation.

Cytotoxic T Cells Recognize and kill infected cells via the release of cytolytic molecules.

Regulatory T Cells Maintain immune balance by preventing overactivation of the immune system.

Memory T Cells Enable faster and stronger responses upon reinfection.

T cells in disease and therapy

T cells play a dual role in health and disease

Infections Essential in clearing viral and bacterial infections, as seen in diseases like HIV and COVID-19.

Autoimmune diseases Malfunctioning T cells can attack the body’s own tissues, leading to conditions like multiple sclerosis and type 1 diabetes.

Cancer immunotherapy CAR-T cell therapy has emerged as a promising treatment for certain types of blood cancers.

Transplantation immunology T cells contribute to graft rejection but can be modulated using immunosuppressive drugs.

Future prospects and challenges

Advancements in T cell engineering Gene editing tools like CRISPR are enhancing T cell therapies.

Targeting tumor microenvironments Overcoming immune evasion mechanisms in cancers.

Balancing immune responses Addressing autoimmunity and immune suppression challenges in therapies.

Conclusion

T cells are indispensable to immune defense, providing specificity, adaptability, and long-term protection. Their roles extend beyond pathogen defense to regulating immune tolerance and shaping immunotherapies. While challenges remain, ongoing research into T cell biology and applications continues to revolutionize medicine, offering hope for treating various diseases. Understanding and harnessing T cells’ potential will be key to advancing future immunological interventions.

Acknowledgement

None

Conflict of Interest

None

References

1. Dawkins HJS, Draghia-Akli R, Lasko P, Lau LPL, Jonker AH, et al. (2018). Clin Transl Sci 11: 11-20.

, ,

2. Sato K, Oiwa R, Kumita W, Henry R, Sakuma T, et al. (2016) . Cell Stem Cell 19: 127-38.

, ,

3. Larcher T, Lafoux A, Tesson L, Remy S, Thepenier V, et al. (2014) PLoS One 9: e110371.

, ,

4. Cui D, Li F, Li Q, Li J, Zhao Y, et al. (2015) Sci Rep 5: 15603.

, ,

5. Thomas ED (1999) . Br J Haematol 105: 330-339.

, ,

6. Blaese RM (1993) . Pediatr Res 33: S49-55.

,

7. Kassner U, Hollstein T, Grenkowitz T, Wühle-Demuth M, Salewsky B, et al. (2018)  . Hum Gene 20: 520-527.

, ,

8. Ahlawat J, Guillama Barroso G, Masoudi Asil S, Alvarado M, Armendariz I, et al. (2020) . ACS Omega 5: 12583-12595.

, ,

9. Kole R, Krainer AR, Altman S (2012) . Nat Rev Drug 11: 125-40.

, ,

10. Li Q (2020) Yonsei Med J 6: 273-283.

, ,