Human mesenchymal progenitor cell

Patent Number: 6936281

This is a composition of matter patent for mesenchymal stem cell progenitors. The first three independent claims of this patent are restricted to generation of these cells from a Dexter type culture system (a specific type of long term culture in which adherent cells are allowed to form a layer and the hematopoietic cells rely on their support). The forth independent claim is not restricted. Although the patent was issued, it appears, at least at first site, to be similar to the mesenchymal stem cell patents that Osiris Therapeutics has.

The authors seem to differentiate themselves from the Osiris patents by stating

"U.S. Pat. No. 5,486,359 to Caplan, et al. is directed to isolated human MSCs, and a method for their isolation, purification, and culturing. Caplan, et al. also describes methods for characterizing and using the purified mesenchymal stem cells for research, diagnostic, and therapeutic purposes. The invention in '359 to Caplan, et al. describes pluri-potential cells that remain pluri-potential, even after cultural expansion. Caplan, et al. also teaches that it is necessary to first isolate the pluri-potent MSCs from other cells in the bone marrow and then, in some applications, uses culture medium to expand the population of the isolated MSCs. This patent fails to disclose the use of Dexter-type cultures, pluri-differentiated mesenchymal progenitor cells, or the isolation of cells from Dexter-type cultures."

whether these above differences are substantially novel and worthy of patent granting should be looked into

The independent claims of the current patent are below:

An isolated pluri-differentiated mesenchymal progenitor cell, wherein said cell is obtained directly from a primary Dexter cell culture wherein said cell simultaneously expresses, at the protein level, a plurality of genes that are markers for multiple cell lineages, wherein said multiple cell lineages comprise at least four different mesenchymal cell lineages, wherein each of said markers is specific for a single cell lineage, and wherein said cell is not a cell of a cell line.

A pharmaceutical composition comprising isolated pluri-differentiated mesenchymal progenitor cells wherein said cells are obtained directly from a primary Dexter cell culture and a pharmaceutically acceptable carrier, wherein said cells individually share the characteristic of simultaneously expressing, at the protein level, a plurality of genes that are markers for multiple cell lineages, wherein said multiple cell lineages comprise at least four different mesenchymal cell lineages, wherein each of said markers is specific for a single cell lineage, and wherein said cells are not cells of a cell line.

A plurality of isolated pluri-differentiated mesenchymal progenitor cells, wherein said plurality of cells are obtained directly from a primary Dexter cell culture wherein said plurality of cells are cells that individually simultaneously express, at the protein level, a plurality of genes that are markers for multiple cell lineages, wherein said multiple cell lineages comprise at least four different mesenchymal cell lineages, wherein each of said markers is specific for a single cell lineage, and wherein said plurality of cells are not cells of a cell line.

A plurality of pluri-differentiated mesenchymal progenitor cells, wherein said plurality of cells are cells that individually simultaneously express, at the protein level, a plurality of genes that are markers for multiple cell lineages, wherein said multiple cell lineages comprise at least four different mesenchymal cell lineages, wherein each of said markers is specific for a single cell lineage, wherein said plurality of cells are not cells of a cell line, and wherein said pluri-differentiated mesenchymal progenitor cells have been isolated from hematopoietic cells and macrophages to a purity of at least 95%.

View this patent on the USPTO website.