Production of interferon in serum-free human leukocyte suspensions.

The recovery of interferon from Sendai-infected suspensions of purified human leukocytes is dependent on the serum concentration in the incubation medium. Very little interferon is obtained from serum-free suspensions. The data reported demonstrate that the critical macromolecular, age-independent, and species-unspecific serum principle can be omitted from the suspensions if the medium is supplemented with a combination of crystalline serum albumin and high concentrations of any one of five studied dipolar ionic buffers [N,N-bis(2-hydroxyethyl) glycine (Bicine), N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), 2-(N-morpholino)ethanesulfonic acid (MES), N-tris(hydroxymethyl)methyl-2-amino-ethanesulfonic acid (TES), and N-tris(hydroxymethyl)methylglycine (Tricine)]. The optimal combination [TES (1.0%, w/v) and bovine serum albumin (0.8%, w/v)] allows the production of potent preparations of serum-free human interferon.