T cells

Definition

T cells are a type of lymphocyte that play a central role in cell-mediated immunity. They are characterized by the presence of T-cell receptors (TCR) on their surface.

5 Must Know Facts For Your Next Test

1. T cells originate in the bone marrow but mature in the thymus.
2. There are two main types of T cells: Helper T cells (CD4+) and Cytotoxic T cells (CD8+).
3. Helper T cells assist other white blood cells in immunologic processes, including the activation of B cells to secrete antibodies.
4. Cytotoxic T cells directly kill infected or cancerous cells by inducing apoptosis.
5. T-cell receptors (TCRs) recognize antigens presented by Major Histocompatibility Complex (MHC) molecules.

Review Questions

• Where do T cells mature?
• What is the primary function of Helper T cells?
• How do Cytotoxic T cells destroy targeted cells?

Related terms

Lymphocyte: A type of white blood cell involved in the adaptive immune response.

B Cell: A type of lymphocyte responsible for producing antibodies.

Major Histocompatibility Complex (MHC):

Proteins on cell surfaces that present antigens to T cells.