Methods for the isolation and expansion of cord blood derived T regulatory cells

1. A method of generating a regulatory T cell (T reg cell) suppressor cell line, wherein said T reg suppressor cell line suppresses T cell proliferation in a mixed lymphocyte reaction by a factor of at least 95% at a ratio of 1:32 (T reg : T cell), said method comprising:

a) isolating a population of mononuclear cells from a human umbilical cord blood sample;

b) contacting said population of mononuclear cells with an antibody that specifically binds CD25 under conditions suitable for formation of a mononuclear cell-antibody complex;

c) substantially separating said mononuclear cell-antibody complex from said population of mononuclear cells; thereby isolating a population of phenotypically CD25 + CD45RA + blood cells;

d) expanding said isolated population of CD25 + cells in the presence of anti-CD3/CD28 antibody coated beads;

e) activating said expanded population of CD25 + cells in the presence of IL-2; and

f) substantially separating said activated population of CD25 + cells; thereby generating a suppressor cell line that suppresses T cell proliferation in a mixed lymphocyte reaction by at least 95% when at a ratio of 1:32 (T reg : T cell).

2. The method of claim 1 , wherein said antibody is selected from the group consisting of an isolated antibody, a biological sample comprising an antibody, an antibody bound to a physical support and a cell-bound antibody.

3. The method of claim 2 , wherein said antibody is selected from the group consisting of a polyclonal antibody, a monoclonal antibody, a humanized antibody, a synthetic antibody, a biologically active fragment of an antibody, and combinations thereof.

4. The method of claim 3 , wherein said biologically active fragment is selected from the group consisting of an Fab fragment, a F(ab′) 2 fragment, a Fv fragment, and an scFv fragment.

5. The method of claim 2 , wherein said physical support is selected from the group consisting of a microbead, a magnetic bead, an absorption column and an adsorption membrane.

6. The method of claim 1 , wherein said mononuclear cell-antibody complex is substantially separated from said population of mononuclear cells by a method selected from the group consisting of fluorescence activated cell sorting (FACS) and magnetic activated cell sorting (MACS).

7. The method of claim 1 , wherein steps b) and c) are repeated.