Description: The eBio341 monoclonal antibody reacts with rat CD8β. CD8β is a member of the immunoglobulin superfamily which heterodimerizes with CD8α to form the CD8 antigen expressed on CD4+CD8+, double-positive thymocytes, the majority of MHC class I-restricted peripheral T cells, and on some macrophages. CD8β expression is absent in athymic mice, which are populated by T-cells expressing CD8α homodimers. This has led to the idea that CD8β expression is dependent on the development of T cells in the thymus. CD8 binds to MHC class I expressed on the surface of antigen-presenting cells during antigen presentation, and participates in T-cell receptor signal transduction through association with the kinase Lck.