doi.bio/t-cell

T cells 1 , also known as T lymphocytes, are a type of white blood cell that plays a central role in cell_mediated immunity.

Derived from hematopoietic stem cells in the bone marrow.

They mature in the thymus, which is where they get their name ("T" stands for thymus).

Types of T cells

Helper T cells (CD4+ T cells)

Activate other immune cells, including B cells and CD8+ T cells.

Recognize antigens presented by MHC class II molecules.

Cytotoxic T cells (CD8+ T cells)

Directly destroy infected or cancerous cells.

Recognize antigens presented by MHC class I molecules.

Regulatory T cells (Tregs)

Suppress or regulate immune responses, preventing autoimmunity and overactive immune reactions.

Memory T cells

Long-lived cells that "remember" previous encounters with pathogens and can mount a rapid response upon re-exposure.

Function

Recognize and respond to foreign antigens.

Coordinate other parts of the immune system.

Play a role in immune memory, allowing the immune system to respond more rapidly and effectively to previously encountered pathogens.

T cell receptor (TCR)

Present on the surface of T cells.

Allows T cells to recognize specific antigens in the form of peptide fragments bound to MHC molecules on the surface of other cells.

Clinical Importance

T cells are targeted by HIV, leading to the progressive loss of immune function in AIDS patients.

T cell therapies, like CAR-T, have been developed for certain cancers.

Autoimmune diseases can result from dysfunctional T cell activity.

Note

T cells are a vital component of the adaptive immune system, distinguishing them from innate immune cells.

Their activity is regulated by a balance of activating and inhibitory signals to ensure a proper immune response without damage to the host.

References

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