Inhibition of activation of DNA synthesis by immune lymphocytes in mixed normal lymphocyte cultures in vitro

Abstract

Replacement of normal by immune lymphocytes as reacting cells in “one-way” mixed lymphocyte cultures (MLC) leads to inhibition of DNA synthesis. this phenomenon is observed regardless of the strain of mice, the method of immunization (in vivo or in vitro), or the method of performing the MLC test (macro-or microcultures, presence of mercaptoethanol in the medium, type of control). Unlike the cytotoxic effect of immune lymphocytes, which follows an acute course with a peak on the eighth day after immunization, inhibition of DNA synthesis in MLC is observed as early as on the second day, it continues for several weeks after immunization, and it can be produced by the addition of a small fraction (5–10%) of immune to normal lymphocytes.