[Immune lymphocyte inhibition of activation of DNA synthesis in mixed cultures of normal lymphocytes in vitro].

Substitution of normal lymphocytes by immune ones as responding cells in the "one-way" mixed lymphocyte culture (MLC) results in inhibition of the DNA synthesis. This phenomenon is reproduced irrespective of the mouse strains used, immunization method (in vivo or in vitro) and various MLC techniques (macro- or microcultures, the presence of mercaptoethanol in the medium, control variants). Unlike the cytotoxic effect of immune lymphocytes showing a sharp peak on the 8th day after in vivo immunization, inhibition of the DNA synthesis activation in MLC occurred as the second day, and persisted for several weeks after immunization; this inhibition was reproduced on addition of a small fraction (5 to 10%) of immune lymphocytes to normal ones.