Human CD28 homolog (CD28H), also known as Transmembrane and immunoglobulin domain-containing protein 2 (TMIGD2) and immunoglobulin and prolinerich receptor 1 (IGPR-1). GenBank Accession No. NM_144615, a.a. 23-128 fused at the C-terminus to the Fc portion of human IgG1 followed by a C-terminal AviTag™ expressed in a HEK293 expression system. MW = 40 kDa. This protein is enzymatically biotinylated using Avi-tag™ technology. Biotinylation is confirmed to be greater than 90%. This protein runs at a higher MW by SDS-PAGE due to glycosylation.