CD133. also known as Prominin-1. is a transmembrane glycoprotein widely recognized as a surface marker for stem and progenitor cells. Identified in the 1990s, CD133 is characterized by five transmembrane domains and extracellular N-glycosylation sites, which contribute to its role in membrane organization and cellular interactions. It is expressed in various stem cell populations, including hematopoietic stem cells, neural stem cells, endothelial progenitors, and cancer stem cells (CSCs).
CD133 antibodies were developed to target specific extracellular epitopes of the protein, enabling the identification, isolation, and characterization of CD133⁺ cells. These antibodies (e.g., clones AC133. AC141) have become essential tools in cancer research, as CD133⁺ CSCs are implicated in tumor initiation, therapy resistance, and metastasis. In regenerative medicine, CD133 antibodies aid in isolating stem cells for therapeutic applications.
Notably, CD133 glycosylation patterns vary across cell types and disease states, influencing antibody binding specificity. For instance, the AC133 epitope is lost upon cell differentiation, highlighting its utility in distinguishing undifferentiated cells. However, discrepancies in antibody performance across experimental conditions (e.g., fixation methods) necessitate careful validation.
Despite challenges, CD133 antibodies remain pivotal in advancing stem cell biology, cancer therapeutics, and biomarker studies, underscoring their dual role in research and clinical translation.