[The suppressive effect of antilymphocyte globulin (ALG) on the formation of anti-ALG antibodies].

The quantitative follow-up of precipitin formation against IgG aids in investigating the question whether ALG when applied to the organism tends to suppress the immune reaction against ALG. Rabbits locally immunized with pig anti-rabbit ALG were repeatedly treated i.v. with the same ALG, and to control groups normal pig IgG and NaCl saline was administered. It was found that antilymphocytic antibodies greatly suppressed the precipitation formation against IgG molecules. In the later stages of application this effect became more pronounced, evidently due to the specific suppression induced by long-term administration of relatively high doses of antigen. A possible improvement in the prevention of precipitin formation in ALG treated patients, i.e. substitution of currently applied tolerogenic dose of normal IgG by a similar dose of ALG is suggested.