The invention provides a quiescent
stem cell having the capacity to differentiate into
ectoderm,
mesoderm and
endoderm, and which does not express
cell surface markers including
MHC class I,
MHC class II, CD44, CD45, CD13, CD34, CD49c, CD73, CD105 CD90, CD66A, CD66E, CXCR4, CD133 or an SSEA. The invention further provides a proliferative
stem cell, which expresses genes including Oct-4, Nanog, Sox2, GDF3, P16INK4, BMI, Notch, HDAC4, TERT, Rex-1, TWIST, KLF-4 and Stella but does not express
cell surface markers including
MHC class I,
MHC class II, CD44, CD45, CD13, CD34, CD49c, CD73, CD105, CD90, CD66A, CD66E, CXCR4, CD133 or an SSEA. The cells of the invention can be isolated from adult mammals, have embryonic
cell characteristics, and can form embryoid bodies. Methods for obtaining the stem cells, as well as methods of treating diseases and differentiated the stem cells, are also provided.