Abstract: A method for purifying an immunosuppressant protein (HISP) has the steps of obtaining supernatant from hNT cells; exposing the supernatant to preparative polyacrylamide gel electrophoresis to produce 20 isoelectric fractions, including active isoelectric fraction #10; placing the active isoelectric fraction on a Blue Sepharose column to bind albumin; and collecting the free fraction containing the concentrated, isolated HISP. Also disclosed is a method of treating inflammation, using an effective amount of an HISP. The HISP is anionic, has a molecular weight of 40-100 kDa, an isoelectric point of about 4.8 and is obtained from the supernatant of hNT cells, but not from NCCIT embryonal carcinoma cells, T98G glioblastoma cells or THP-1 monocytic leukemia cells. HISP can maintain T cells in a quiescent G0/G1 state without lowering their viability. HISP loses activity when treated with heat, pH2, pH11, or mixed with trypsin or carboxypeptidase, but not with neuraminidase.

Abstract: A method of improving the survival of neuronal cells has the steps of obtaining a frozen cellular composition comprising neuronal cells; thawing the cellular composition; and contacting the cellular composition with a balanced electrolyte solution including a lithium salt. One example of a lithium salt is lithium chloride. Also is provided a kit comprising a container of with a cellular composition comprising neuronal cells and a container of a diluent comprising a balanced electrolyte solution and a lithium salt.