Abstract: An interleukin-2 preparation that is extremely pure, stable when stored for a long time, and appropriate for therapeutic purposes, especially in humans, and that also exhibits sufficient activity even after being frozen and thawed several times is obtained by using a special albumin, globulin, or mixture of those substances with sugar alcohols, monomeric or polymeric sugars, gelatins, or other known stabilizers as stabilizers.

Abstract: The use of pterins to increase the activity of lymphokines and other cell growth factors, and a diagnostic or theraupeutic preparation that contains pterins combined with lymphokines. Adding pterins to lymphokines can increase the activity of the lymphokines by 3 to 5 times.

Abstract: Monoclonal antibodies that recognize a structure common to human interleukin-2 and to the light .lambda. chain of human immunoglobulin and lines of hybridoma cells that produce these monoclonal antibodies can be prepared by immunizing animals, especially mice, with human interleukin-2 (TCGF) and fusing the splenocytes obtained from the animals with animal, expecially mouse, myeloma cells to create a hybridoma. The hybridomas are raised as clones and the antibodies obtained from the individual clones tested for their specificity to human interleukin-2 (TCGF). Clones that produce antibodies with a specificity to human interleukin-2 (TCGF) are selected for further raising to prepare the antibody. The antibody is harvested from the culture medium or from the ascitic fluids of the animal, especially the mouse, with the hybridoma.

Abstract: Crude interleukin-2 extract is subjected to group-selective dye-ligand absorption chromatography in one or more stages of purification with a matrix-gel medium consisting of a Blue A ligand or variant thereof or of a Green A ligand in a concentration of approximately 1.5 to 3.0 mg/ml of expanded matrix at a pH of approximately 6.8 to 8.5, a temperature of approximately 4.degree. to 40.degree. C., and a flowthrough rate of approximately 10 to 100 ml/h, employing an eluent. Either PHA-free or extremely pure interleukin-2 is obtained, depending on the overall number of purification stages.