This antibody specifically targets the CD99 antigen, a 32 kDa sialoglycoprotein expressed across all leukocyte lineages (1-2). CD99, also known as the E2 antigen or MIC2 gene product, is differentially expressed during the development of T and B lymphoid cells as well as granulocytes3. Higher densities of CD99 are observed during early hematopoietic stages, while mature granulocytes exhibit minimal to no expression of this antigen (3-4).
The E2 antigen plays a crucial role in T-cell adhesion processes and is implicated in various hematopoietic adhesion pathways5. This functional involvement underscores its importance in the regulation of immune responses and cellular interactions within the hematopoietic system 5 .