Re: Are there any common antigens for all human cells?

There are many antigens that are common to virtually all nucleated cells. 
Most of the molecular machinery of the cell is common to every system. 
This includes the golgi, endoplasmic reticulum, ribosomes, mitochondria, 
along with the proteins of the metabolic pathways, and many of the 
structural proteins. On the surface of cells, the number of common 
antigens is probably quite low. Class I HLA (Human Leukocyte Antigen) 
molecules are found on virtually all nucleated cells. They are important 
in cell-cell recognition and are responsible for graft transplant 
rejection. Virtually all hematopoetic cells express CD45 (Cluster 
Determinant 45), although it is not found on all other nucleated cells.