Recombinant human CD3d (CD3 delta) protein fused with an Fc tag, used in immunological research to study the T cell receptor (TCR) complex assembly, signaling pathways, and protein interactions. As a key subunit of the CD3 complex on T cells, this fusion protein enables investigation of CD3-TCR associations and modulation of T cell activation. Commonly applied in flow cytometry, ELISA, Western blot, and protein-protein interaction assays to detect and quantify CD3 components in human samples. The Fc tag facilitates straightforward purification using Protein A/G columns and detection via anti-Fc antibodies, enhancing its utility in functional assays and immunotherapy development.