Natural killer cells

An ex vivo method for increasing the number of CD16+ NK cells in an expanded NK cell population, comprising the steps of:

• a) culturing an haematopoietic progenitor cell (HPC) comprising sample obtained from an individual in medium which does not induce differentiation of the HPCs for between about 2 to about 8 days to produce a pre-differentiation HPC population;
• and
• b) culturing the pre-differentiation HPC population in medium which induces differentiation of the HPCs to NK.

A method according to any one of the preceding claims, wherein the HPCs are cultured in the presence of a Notch ligand for at least part of step (a).

A method according to any one of the preceding claims, wherein:

• (i) in step (a) the HPCs are cultured in the presence of a compound which inhibits the action of REV-ERB;
• and/or
• (ii) in step (b) the pre-differentiation HPC population is cultured in the presence of a compound which inhibits the action of REV-ERB.

A method according to any one of the preceding claims, wherein the medium which does not induces differentiation of the HPCs in step (a) and/or the medium which induces differentiation of the HPCs to NK in step (b) does not comprise IL-3, preferably wherein the medium which induces differentiation of the HPCs to NK in step (b) does not comprise IL-3.

A method according to any one of the preceding claims, wherein:

• (i) the medium in step (a) comprises at least one of Flt3L, GM-CSF, IL-3, IL-6, TPO and/or stem cell factor (SCF), preferably Flt3L, GM-CSF, IL-3, IL-6, TPO and SCF;
• and/or
• (ii) the medium in step (b) comprises IL-7, Flt3L, IL-15, and/or SCF, preferably IL-7, Flt3L, IL-15 and SCF.

A method according to any one of the preceding claims, wherein the step (a) and/or step (b) is carried out in the absence of a stromal support cell, preferably wherein both step (a) and step (b) are carried out in the absence of a stromal support cell.

A method according to any one of the preceding claims, wherein the sample of HPCs is obtained from bone marrow, cord blood and/or peripheral blood.

A method according to any one of the preceding claims, wherein the proportion of CD16+ NK cells is increased compared with the proportion of CD16+ NK cells produced by a corresponding method in which step (a) is omitted.

A method according to any one of the preceding claims, wherein the expanded NK cell population comprises at least 10% CD16+ NK cells, preferably at least 15% CD16+ NK cells, more preferably at least 20% CD16+ NK cells, even more preferably at least 30% CD16+ NK cells.

A method according to any one of the preceding claims, wherein the expanded NK cell population exhibits at least 30% greater antibody-dependent cellular cytotoxicity (ADCC), preferably at least 50% greater ADCC, compared with NK cells produced by a corresponding method in which step (a) is omitted.

A method according to any one of the preceding claims, wherein which does not comprise a further step of introducing exogenous nucleic acid into the HPCs and/or NK cells.

An expanded population of CD16+ NK cells, wherein at least 10% of the NK cells are CD16+ NK cells, preferably at least 15% of the NK cells are CD16+ NK cells, more preferably at least 20% of the NK cells are CD16+ NK cells, even more preferably at least 30% of the NK cells are CD16+ NK cells.