Studies on the stability of antilymphocyte globulins

An account is given of the effect of storage under various conditions on the physical and immunosuppressive properties of antilymphocyte globulins. No loss of in vivo immunosuppressive potency was shown by horse antimouse lymphocyte globulin when stored for up to 2 years in a liquid, frozen, or lyophilised state. Similar studies on horse antihuman lymphocyte globulin showed no loss of in vitro activity, as measured by an immunofluorescence test. Ultracentrifugal analyses showed no increase in aggregate when antilymphocyte globulin was stored liquid or freeze-dried at 4 degrees C. Storage experiments at abnormally high temperatures demonstrated that under these conditions freeze-dried horse antihuman lymphocyte globulin was stabilised by the presence of glucose (4.6%w/v). Antilymphocyte globulin lyophilised in the presence of glucose showed improved solubility properties as compared with material dried from saline.