Composition for culturing natural killer cells and method for preparing natural killer cells by using same

A method for culturing a natural killer cell without CD3+ or CD56-cells, which comprises:

• i) isolating a cell, comprising one of (A), (B), or (C):
• (A) isolating a cell that does not express CD3 from peripheral blood mononuclear cells (PBMCs),
• (B) isolating a cell that expresses CD56 from PBMCs, or
• (C) isolating a cell that does not express CD3 from PBMCs, and isolating a cell that expresses CD56 from the cell that does not express CD3, isolated in the first isolating step;
• and
• ii) culturing the isolated cell in the presence of a fusion protein dimer,
• wherein the fusion protein comprises the following structural formula (I) or (II):
• N′—X-[linker (1)]n-Fc domain-[linker (2)]m-Y—C′— formula (I)
• N′—Y-[linker (1)]n-Fc domain-[linker (2)]m-X—C′— formula (II),
• wherein, N′ is the N-terminus of the fusion protein,
• C′ is the C-terminus of the fusion protein,
• X is a CD80 protein or a fragment thereof,
• Y is an IL-2 variant thereof,
• the linkers (1) and (2) are peptide linkers, and
• n and m are each independently 0 or 1,
• wherein the CD80 fragment comprises the extracellular domain of CD80,
• wherein the IL-2 variant has any one selected from the following substitution combinations (a) to (d) in the amino acid sequence of SEQ ID NO:
• 10:
• (a) R38A/F42A
• (b) R38A/F42A/Y45A
• (c) R38A/F42A/E61R
• (d) R38A/F42A/L72G.