BIO444 T Cell Functions

Effector T Cells

Activated immune cells that migrate to sites of infection to eliminate microbes.

CD4+ T Cells

A subset of T cells that help B lymphocytes produce high-affinity antibodies.

Extravasation

The process by which activated T cells migrate to infected tissues.

Integrins

Cell surface molecules that enable effector T cells to home to inflamed tissue.

Cytotoxic T Cells

T cells that kill infected cells through a process involving binding, granule rearrangement, and target cell death.

CD8+ T Lymphocytes (CTLs)

A type of cytotoxic T cell that synthesizes cytotoxins to kill infected cells.

Granzymes

Enzymes contained in cytotoxic granules that initiate cell death in target cells.

Perforin

A cytotoxin that creates pores in the target cell membrane to deliver granzymes.

Apoptosis

Programmed cell death that occurs in target cells after CTL attack.

Th1 Cells

A subset of CD4+ T cells that enhance APC activity and protect against intracellular pathogens.

Th2 Cells

A subset of CD4+ T cells that protect against extracellular pathogens and are involved in allergic responses.

Th17 Cells

A subset of CD4+ T cells that induce inflammatory reactions against extracellular bacteria and fungi.

Cytokines

Signaling molecules produced by T cells that determine their functions and responses.

IL-12

A cytokine that drives the differentiation of Th1 cells.

IFN-γ

A signature cytokine of Th1 cells that activates macrophages.

Tregs (Regulatory T Cells)

CD4+ T cells that suppress immune responses and maintain self-tolerance.

TFH Cells (Follicular Helper T Cells)

T cells that help B cells produce antibodies.

Memory T Cells

Long-lived T cells that respond rapidly upon re-exposure to an antigen.

CTLA-4

An inhibitory receptor that downregulates immune responses.