CD28

biology

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Last updated

July 21, 2026

Quick Summary

CD28 is a protein found on the surface of helper T cells. It plays a crucial role in activating these cells by binding to a molecule called B7 on antigen-presenting cells. This interaction, along with other signals, helps the immune system recognize foreign substances and initiate a response. Helper T cells are vital white blood cells that orchestrate immune functions by activating other immune cells, such as B cells (which produce antibodies) and macrophages, to fight infections. CD28 is distinct from CD4, which is also found on helper T cells and binds to different molecules on antigen-presenting cells. CD8, on the other hand, is a related protein found on cytotoxic T cells.123

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James P. Allison
…his laboratory there, he identified CD28 as a necessary costimulatory signaling molecule required for T-cell activation. He and colleagues also found that a molecule known as CTLA-4 opposed CD28 and played a critical role in the downregulation of immune responses. When injected into tumours in mice, CTLA-4 antibody, designed to…
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…his laboratory there, he identified CD28 as a necessary costimulatory signaling molecule required for T-cell activation. He and colleagues also found that a molecule known as CTLA-4 opposed CD28 and played a critical role in the downregulation of immune responses. When injected into tumours in mice, CTLA-4 antibody, designed to…
Read More