Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2009
Publication Date: 3/1/2010
Citation: Mao,W., Hunt, H.D., Cheng, H.H. 2010. Cloning and Functional Characterization of Chicken Stem Cell Antigen 2. Developmental and Comparative Immunology. 34(3):360-368. Interpretive Summary: The large majority of chicken proteins are hypothetical with unknown function. Of these unknown proteins, stem cell antigen 2 (SCA2) is of interest because of its potential role in the development of immune cells, especially lymphocytes. In this study, we report the generation of a specific antibody to track SCA2 protein. We find that it is expressed on a number of tissues and, most interestingly, in connective tissues in the bursa of Fabricius, the origin of B cells. This result suggests that SCA2 may interact with B cells during their development in the bursa. The antibody will greatly aid in our ability to further characterize the biology function of SCA2 in chicken, which will aid in our overall understanding of the chicken immune system.
Technical Abstract: Stem cell antigen 2 (SCA2) is a Ly-6 family member whose function is largely unknown. To characterize biological properties and tissue distribution of chicken SCA2, SCA2 protein was expressed and purified in E. coli, and a polyclonal antibody developed. Utilizing the polyclonal antibody SCA2 is a 13 kDa cell surface protein anchored by a glycosyl-phosphatidylinositol (GPI) moiety. SCA2 was expressed on the cell surface of a reticuloendotheliosis virus (REV) transformed avian T lymphoid cell line. The tissue distribution of SCA2 shows that SCA2 is expressed in hepatocytes and connective cells of thymus and bursa based on immunohistochemistry, immunoprecipitation and western blots. In bursa follicles, SCA2 is specifically expressed on the cortical-medullary epithelial cells (CMEC) surrounded with MHC class II presenting cells suggesting that SCA2 may play roles in B cell development by interacting with ligands on the B cell surface.