CD4 T helper cells are a type of white blood cell called a lymphocyte that serves an important role in your immune system. These cells help defend the body against infection by directing other ...

Some, known as dendritic cells, take up proteins from foreign pathogens, chop them up into peptides called antigens, and display them on their surface. Another group, known as helper T cells, inspects ...

The body’s defense system against infection also fights tumors, generating tumor resident stem-like T cells and killer T cells that express inhibitory receptors such as PD-1. When PD-1 binds to PD-L1 ...