Method for isolating, removing and analyzing cells

A method for isolating, removing and/or analyzing activated cells, including:

• filtering a liquid sample containing the cells with a polyimide porous film, and examining one or more cell properties selected from the group consisting of the number or type of cells, external or internal structure of the cells, type or amount of cell surface antigens, type or amount of substances secreted from the cells, cell adhesion and cell survival rate for the cells that were captured in the polyimide porous film without being filtered by the film as well as cells in the liquid sample that passed through the polyimide porous film,
• wherein the polyimide porous film has a three-layer structure consisting of an A-surface layer having a plurality of pores, a B-surface layer having a plurality of pores, and a macro-void layer sandwiched between the two surface layers,
• a mean pore size in the A-surface layer is smaller than a mean pore size in the B-surface layer, and
• the macro-void layer has a partition bonded to the A-surface layer and the B-surface layer, and a plurality of macro-voids surrounded by the partition, the A-surface layer, and the B-surface layer.