Composition and method for preserving progenitor cells

A method of enriching progenitor cells, comprising culturing progenitor cells in a progenitor-preserving amount of a protein having an amino acid sequence comprising SEQ ID NO:3 and a molecular weight of about 15-20 kD, or having an amino acid sequence comprising SEQ ID NO:1 and a molecular weight of about 12-20 kD, wherein the protein specifically preserves the progenitor cells, and wherein the culturing is performed under conditions permitting preservation of progenitor cells while permitting the number of differentiated cells to decrease.

A method of improving hematopoietic competence in a mammal, comprising:

• a) culturing a tissue sample comprising hematopoietic progenitor cells in a growth medium containing a protein having an amino acid sequence comprising SEQ ID NO:1 and a molecular weight of about 12-20 kD, or having an amino acid sequence comprising SEQ ID NO:3 and a molecular weight of about 15-20 kD, in an amount sufficient to preserve the progenitor cells and to provide cultured cells enriched in the progenitor cells;
• and
• b) transfusing the enriched cultured cells to the mammal to provide progenitor cells for generating blood cellular components in the mammal.

In a method of transfecting an exogenous DNA sequence into somatic cells,

• the improvement comprising transfecting progenitor cells selectively preserved by a protein having an amino acid sequence comprising SEQ ID NO:1 and a molecular weight of about 12-20 kD, or having an amino acid sequence comprising SEQ ID NO:3 and a molecular weight of about 15-20 kD.

A composition for maintaining viability of progenitor cells ex vivo, comprising a cell growth medium and a protein which preserves progenitor cells, wherein the protein has an amino acid sequence comprising SEQ ID NO:1 and a molecular weight of about 12-20 kD, or has an amino acid sequence comprising SEQ ID NO:3 and a molecular weight of about 15-20 kD.