Development of suppressor T lymphocytes for Epstein-Barr virus-induced B-lymphocyte outgrowth during acute infectious mononucleosis: assessment by two quantitative systems.

A system of 3H-thymidine incorporation by lymphocytes in culture for 3 wk has been utilized for quantitative assessment of the ability of T lymphocytes to inhibit outgrowth of autologous Epstein-Barr virus (EBV) transformed B lymphocytes. Lymphocytes from EBV-seronegative individuals lack the ability to suppress outgrowth of autologous EBV-transformed B lymphocytes. This capability appears during the course of primary EBV-induced infectious mononucleases (IM) as the atypical lymphocytosis is subsiding and persists for years after recovery from primary EBV infection. The ability of T lymphocytes from EBV-seropositive subjects or convalescent IM patients to inhibit B-lymphocyte outgrowth is not HLA restricted. Thus, T lymphocytes capable of inhibition of in vitro EBV-induced B-cell outgrowth emerge during the acute stage of IM and may represent an important control mechanism of EBV-induced B-lymphocyte proliferation in vivo. The system provides a highly sensitive quantitative means for in vitro assessment of cell-mediated immunity to EBV.