Versuche zur Beeinflussung des immunologischen Gedächtnisses

Abstract

The elimination of primed antibody‐forming cells and memory cells was examined in Sprague‐Dawley rats after the application of cyclophosphamide. Doses of cyclophosphamide, which completely eliminate virgin sheep red blood cell‐(SRBC)‐specific competent cells, still permit the survival of a fraction of primed cells. In animals devoid of primed cells it is possible to establish SRBC‐specific tolerance upon cyclophosphamide treatment. When SRBC‐primed rats are treated with the drug and subsequently exposed to the antigen, the surviving primed cells are stimulated to proliferation and antibody production, whereas tolerance appears to be induced in the competent cells, which regenerate from the stem cell compartment.

Different Suppressive Effects of Combined Cyclophosphamide-Antigen Treatment Compared with Exclusive Cyclophosphamide Treatment on Primary and Secondary Humoral Immune Reactivity

“…This is unfortunate on the one hand because the majority of clinical cases in which sup pression of immunological reactivity is de-sirablc are characterized by extensive sec ondary reactivities (autoaggressive diseases, graft rejection), and on the other hand be cause up to now immunosuppressive treat ment against secondary responses has been considered much more difficult to carry out. For example, CY treatment in rats, even when given in a dosage of LD90, could not suppress preexisting immunological sensiti zation [12]. However, in previous studies we were able to show that the combination of CY with renewed antigen exposure en ables inhibition (sometimes complete elimina tion) of preexisting immunological sensitiza tion [13].…”