Abstract
Peripheral lymphocytes obtained from two individuals with a previous history of infectious mononucleosis were exposed to mitomycin‐treated cells of the autologous lymphoblastoid cell line (LCL) established during the acute phase of the disease. This resulted in a stimulation of DNA synthesis, comparable to or even exceeding a one‐way MLC with allogeneic lymphocytes. The cytotoxic effect of the stimulated lymphocytes was tested by colony inhibition or ^51^Cr release, against a large LCL panel, including the autologous line and allogeneic lines from patients with Burkitt's lymphoma (BL), nasopharyngeal carcinoma (NPC), infectious mononucleosis (IM), leukemia, myeloma, or normal donors. While the majority of the lines were highly sensitive to the killing action, three were relatively resistant. The same pattern of sensitivity was obtained with effector cells stimulated by autologous LCL derived from IM or BL patients. The majority of the target LCLs had B‐cell characteristics and carried the EBV genome, but three cell lines that were devoid of the EBV genome, were also sensitive. These lines included two lymphoid cell lines, one of them a T‐cell line, and a myeloma line. Fresh peripheral lymphocytes from normal donors or acute IM patients, PHA‐induced blasts and blast cells from a case of acute myeloid leukemia were resistant.