CD4-positive T cell (CD4+ T cell)

CD4-positive T cell Overview

CD4-positive T cells, also known as CD4+ T lymphocytes or helper T cells, are a critical subset of white blood cells that play a central role in the adaptive immune system. They are characterized by the expression of the surface glycoprotein CD4 and assist other immune cells in mounting an effective immune response. Upon activation, they differentiate into several functionally distinct subsets, including Th1, Th2, Th17, Th22, Treg, and Tfh cells, each with specific roles in immunity. CD4+ T cells stimulate other immune cells through direct contact and cytokine secretion, coordinating both innate and adaptive immunity. Normal adult levels range from approximately 500–1200 CD4+ cells per mm³ blood; lower counts indicate immunodeficiency states such as HIV/AIDS where these populations are depleted.

Mechanism of Action

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Biological Functions

Safety Considerations

Associated Biomarkers