Immunostimulation or immunodepression?

Our experimental studies and extensive literature survey established that the overall response of an experimentally modified host defense system is strongly dose-dependent, irrespective of either the modifying agent or the test model system. If a sufficiently broad dose range is used, an irregular, nonlinear, nonmonotonic response curve is formed, generally W- or M-shaped, depending on the parameters selected for the representation, with two peaks of relative maximal effect. Accordingly, a modifying agent may exhibit, in some cases, dual effect--stimulation and depression, each at different dose levels. This typical response is defined as characteristic of the entire host defense system and therefore implies a biologically integrated system. The described dose-response relationship mandates the use of multiple doses in evaluation experiments, to establish efficacy and especially to design optimal dose schedules for experimental and clinical application of any agent modifying the host defense system activity.