The effect of antilymphocyte globulin (ALG) on precipitin formation to human serum albumin in rabbits.

The effects of pig anti-rabbit ALG on precipitin formation to human serum albumin were studied in rabbits with an aim to contribute to an elucidation of the effects of ALG on the humoral antibody response. Antibody levels were assayed quantitatively after the first, second and third local injection of antigen with adjuvant. ALG was found to suppress distinctly, though not completely precipitin formation throughout the immunization cycle in the experimental group compared to the control groups injected with pig IgG or saline at the same time intervals. The immunosuppressive effect was particularly pronounced after the third injection of antigen which did not further increase antibody levels in experimental animals as compared to the controls. The system appears to be effective in partial suppression of the humoral antibody response when a good preparation with appropriate dosage and timing is used.